Cetaceans in Greece: Present status of knowledge

Transcription

1 Cetaceans in Greece: Present status of knowledge Technical Report Initiative for the Conservation of Cetaceans in Greece Prepared by Dr. Alexandros Frantzis July

2 Suggested citation for this technical report Frantzis A Cetaceans in Greece: Present status of knowledge. Initiative for the Conservation of Cetaceans in Greece, Athens, Greece, 94 pp. Note regarding this document This document, together with the National Conservation Strategy and Action Plan for the Conservation of Cetaceans in Greece is the result of a collaboration between four non-governmental organisations MOm, Pelagos Cetacean Research Institute, Tethys Research Institute and WWF Greece intended to advance the conservation of cetaceans in Greece through joint, coordinated actions of its members. These organisations agreed that the goal of conserving cetaceans can be achieved more effectively through cooperative work than through isolated efforts. Note regarding the drawings in this document All cetacean drawings were made by Massimo Demma/ICRAM and kindly offered for the needs of this report. No reproduction is allowed without prior written permission. Note on the property of data of this document This report contains unpublished data. Although proper citation of information included in the document is allowed, no reproduction, use or re-analysis of original data are allowed without prior written authorization by the author. Cover photo Striped dolphins in the Gulf of Corinth. A. Frantzis / Pelagos Cetacean Research Institute

3 Organisations supporting the Initiative for the Conservation of Cetaceans in Greece MOm, The Hellenic Society for the Study and Protection of the Monk Seal Solomou Athens Greece Tel.: Website: Pelagos Cetacean Research Institute Terpsichoris Vouliagmeni Greece Tel.: Website: Tethys Research Institute c/o Acquario Civico Viale G.B. Gadio Milano Italy Tel.: Website: WWF Greece Filellinon Athens Greece Tel.: Website: 1

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5 CONTENTS ORIGIN AND SCOPE OF THIS REPORT 5 EXECUTIVE SUMMARY 7 CETACEAN TERMINOLOGY AND COMMON NAMES IN GREEK 9 METHODS AND DATASET 11 INFORMATION FROM CETACEAN RECORDS 15 SUMMARISED INFORMATION ON COMMONLY OCCURRING SPECIES 19 CETACEAN SPECIES COMMONLY OCCURRING IN THE GREEK SEAS 21 Fin whale, Balaenoptera physalus ( ) 23 Sperm whale, Physeter macrocephalus ( ) 27 Cuvier s beaked whale, Ziphius cavirostris ( ) 31 Risso s dolphin, Grampus griseus ( ) 35 Common bottlenose dolphin, Tursiops truncatus ( ) 39 Striped dolphin, Stenella coeruleoalba ( ) 43 Short-beaked common dolphin, Delphinus delphis ( ) 47 Harbour porpoise, Phocoena phocoena ( ) 53 RARE CETACEAN SPECIES IN THE GREEK SEAS AND AROUND THEM 57 Humpback whale, Megaptera novaeangliae ( ) 59 Minke whale, Balaenoptera acutorostrata ( ) 61 False killer whale, Pseudorca crassidens ( ) 63 Beaked whales, Mesoplodon sp. ( ) 65 Rough-toothed dolphin, Steno bredanensis ( ) 67 FALSE REPORTS OF CETACEAN SPECIES IN THE GREEK SEAS 69 WHAT IS KNOWN, WHAT REMAINS UNKNOWN 71 ARE THE GREEK CETACEAN POPULATIONS DECLINING? 73 ACKNOWLEDGEMENTS 75 LITERATURE CITED 76 ANNEX I Distribution of searching effort in the Greek Seas 83 ANNEX II Distribution maps of sightings and strandings 84 ANNEX III Additional references on the cetaceans of the Greek Seas 93 3

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7 ORIGIN AND SCOPE OF THIS REPORT The Greek Seas host a large number of different cetacean species and constitute an important marine area within the Mediterranean Sea. Over the last decades there has been limited effort invested in the study of cetacean species by various national and international research and conservation groups. Current and past research activities have been focused in distinct areas resulting in a patchy mosaic of our knowledge on cetaceans across Greece. These studies provide strong evidence for the continuous decline in the abundance of cetacean species in the Greek Seas and increasing anthropogenic mortality, suggesting the urgent need for conservation actions. The lack of substantial funding on a national scale basis, the failure of national and international authorities to secure protection for cetaceans and the absence of joint initiatives among the various research and conservation cetacean expert groups has become a major obstacle in effectively addressing the continuous degradation of marine ecosystems and of the decline of cetacean species in Greece. The present document represents the first and an important step towards a new joint initiative for the conservation of cetacean species in the Greek Seas. The new initiative is a common effort between research groups, institutes, environmental NGOs and individual experts dedicated for decades to the research and active conservation of the marine environment and marine mammals. MOm/Hellenic Society for the Study and Protection of the Monk Seal, Pelagos Cetacean Research Institute, WWF-Greece, Tethys Research Institute and Dr. Giuseppe Notarbartolo di Sciara comprise the core of the new initiative, which was established to tackle the cetaceans issue. The participants of the new initiative have planed a number of tasks for the forthcoming future, first of which is the "Technical Report on Cetaceans in Greece: Present status and distribution. This document, presenting the current status of knowledge of the cetaceans in Greece, will serve as the scientific basis upon which we will built the appropriate strategy for the conservation of cetaceans throughout the country and will guide our common efforts to advance and ultimately achieve the common goal of ensuring the recovery and long-term viability of whales, dolphins and porpoises in Greek waters. On behalf of the participants of the initiative, Dr. Spyros Kotomatas Director of MOm 5

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9 EXECUTIVE SUMMARY From 1991 to 2008 data on the presence and distribution of cetaceans in the Greek Seas have been systematically gathered in a database that - together with some older historical records - accounted for 1416 sightings and 1392 stranded animals. Data originated from dedicated surveys, stranding reports, opportunistic sightings, scientific publications and published or unpublished photographic and video documentation. These data provide a solid overview on the species composition of the Greek cetacean fauna. Species diversity, underestimated in the past, is supported by the variety of habitats off the Greek coasts. Eleven cetacean species have been identified within the limits of the Greek Seas (defined by the national borders and the encompassed international waters). Six species are present year-round in all or many of the Greek Seas: striped dolphin (Stenella coeruleoalba), common bottlenose dolphin (Tursiops truncatus), short-beaked common dolphin (Delphinus delphis), Cuvier's beaked whale (Ziphius cavirostris), sperm whale (Physeter macrocephalus) and Risso's dolphin (Grampus griseus). Two species, the harbour porpoise (Phocoena phocoena) and the fin whale (Balaenoptera physalus), have been recorded locally in all seasons and at least the former is likely to be present year round; however, more data are required to understand patterns of seasonality in distribution and occurrence. The remaining three species - humpback whale (Megaptera novaeangliae), false killer whale (Pseudorca crassidens) and common minke whale (Balaenoptera acutorostrata) - have rarely been recorded in the Greek Seas. One more species (not included in our dataset) - the rough-toothed dolphin (Steno bredanensis) - was recorded in offshore waters in proximity to the Greek Seas (central Ionian Sea). Six species have been erroneously included in the Greek cetacean fauna in the past, due to wrong assumptions, false identifications or lack of minimal supporting evidence: white whale (Delphinapterus leuca), Sowerby's beaked whale (Mesoplodon bidens), Blainville's beaked whale (Mesoplodon densirostris), long-finned pilot whale (Globicephala melas), killer whale (Orcinus orca), and blue whale (Balaenoptera musculus). The cetacean species recorded in the Greek Seas can be divided in three major categories according to their distribution. The striped dolphin, the common bottlenose dolphin, the sperm whale and the Cuvier s beaked whale seem to be present in the entire range of the bathymetry/habitat that is considered typical for them. The short-beaked common dolphin, the fin whale and the harbour porpoise have heterogeneous distributions within their potential habitats. The Risso s dolphin can be predictably found only in few areas, although its occasional occurrence was documented in most portions of the Greek Seas. 7

10 According to the distribution maps presented in this Report, the general geographic range of each cetacean species is known with sufficient detail to allow some general conclusions or general comparisons with future data. However, gaps of knowledge still exist at the level of local seas, with the exception of the entire Ionian Sea, west and south Hellenic Trench and Gulf of Corinth. Surveys in several areas of the Aegean Sea are acutely needed to map some species range with higher precision. Since sighting data have been collected primarily (but not exclusively) during the warm season, winter surveys are also necessary to detect possible movements and seasonal changes in the range of some cetacean species. Data regarding ecology and feeding habits, genetics and stock discreteness, life history, toxicology, histopathology, causes of death, biometry etc. are scarce and fragmentary. Limited information is available on anthropogenic threats and their relative importance per species. Such data are crucial for species conservation and for the management of human activities that have an impact on their populations. Although their collection is relatively easy and inexpensive, the lack of a properly organised national stranding network leaves a large number of cetacean carcasses uninspected, resulting in loss of valuable information. Finally, the most important gap of knowledge concerns the absolute abundance of each species population. With the exception of two small and local dolphin population units of common bottlenose dolphins and short-beaked common dolphins, and of the sperm whales, not even rough estimates of abundances are available for any species in the Greek Seas. Without such quantitative data, it is very difficult to adopt proper conservation policies and to monitor the effectiveness of any conservation measure at the national level. Although no population trends are available for any cetacean species in the Greek Seas, local studies, knowledge from other Mediterranean areas, evidence of increasing threats, as well as the apparently small size or uniqueness of several cetacean populations in the Greek Seas, all call for urgent conservation measures. As the local population units of four species in the Greek Seas that are considered Endangered (sperm whale, short-beaked common dolphin, harbour porpoise) or Data deficient (Cuvier s beaked whale), are likely among the most important in the entire Mediterranean Sea, ensuring their long-term survival should be a national priority for the marine environment in Greece. 8

11 CETACEAN TERMINOLOGY AND COMMON NAMES IN GREEK The use of incorrect terminology to refer to cetacean species is still widespread in Greece. This is mainly due to incorrect or literal translations of foreign documentaries and books with no scientific consultancy. Misleading common names are particularly widespread in the national media. This chapter intends to contribute to the adoption of a consistent sciencebased terminology. Most of the terminology problems start from the incorrect translation of the term whale in Greek as (falaina), although the correct translation is (kitodes = cetacean). Unfortunately, the term whale is used in English with two different meanings. Sensu lato it constitutes a synonym of the word cetacean, but sensu stricto it means large cetacean, which does not constitute a taxon and therefore adds to the confusion while translating from English to Greek. The term whale sensu lato covers all whales, dolphins and porpoises. That s why in English the distinction between large whales and small whales (sometimes including dolphins) or baleen whales (mysticetes = ) and toothed whales (odontocetes = ) are often used instead of the general term whale. According to the above the correct translation of the term whale (sensu lato) in Greek is and not. The word should be used only for the translation of the terms baleen whale (literally ) or mysticete. The commonly used Greek term or should also be avoided for the translation of baleen, since the latter originates from the Greek term that passed in Latin as balaena and later gave the term baleen in English. The right word to use for the characteristic plates of whalebone in the mouth of mysticetes (baleens) is. This term makes immediately the link between all the mysticetes or and their taxonomic characteristic, which is the baleen or. For all the above mentioned reasons the translation of the term toothed whale as is incorrect since no cetacean exists that bears both teeth and baleens. Accordingly, baleen whale should not be translated as, a term that constitutes a pleonasm, since all whales bear baleens by definition. As a consequence of the incorrect translation of the term whale, many odontocetes or even dolphins were called (baleen whales). Some of the most characteristic examples are the incorrect translations of killer whale, pilot whale, beaked whale and sperm whale, to,, and, respectively. However, none of these species are (baleen whales), since they do 9

12 not belong to the suborder of mysticetes. In addition the first two of them are dolphins (i.e. belong to the odontocete family of delphinids). The right common names for these species or families are,, and. The Greek common names of cetacean species used in this report are those proposed by Frantzis et al and used in ACCOBAMS (2002) and IUCN (2006) documents. Greek name transcriptions in Latin characters in parenthesis follow ELOT (1982). The symbols of the International Phonetic Alphabet (IPA) and tonic accents have been used to describe their pronunciation in Greek. For the reader who is not familiar with these symbols a few examples follow: i= see, ð= this, j= yours, = ring, x= Scottish loch. No English equivalents exist for the symbols c and. However the closest sounds for the use of c are kye in fócena (harbour porpoise) and kyee in cinó ðelfíni (common dolphin). The sound of in me ápteri fálena (humpback whale) is between g in the word mega and y in the word yes. 10

13 METHODS AND DATA USED The study area The Greek Seas include the east Ionian, the Aegean, the Cretan and the north-west Levantine Seas as well as the northern Cretan Passage between Crete and North Africa. They occupy the northern part of the eastern Mediterranean (roughly between N and E) and are characterised by: (a) pronounced oligotrophy in most of their range, (b) highly irregular and very long coastline (>15,000 km) that accounts for one third of the total Mediterranean coastline, (c) almost 10,000 islands and islets, (d) some extended plateaux and (e) steep underwater relief of depressions and trenches reaching a maximum depth of 5121m south-west of the Peloponnese (Stergiou et al. 1997). This rich geomorphology (Figure 1) creates a variety of marine ecosystems and habitats for various cetacean species. Figure 1. Map of the Greek Seas showing their bathymetry and the locations mentioned in this report. 1: Lefkada Island, 2: Kefallonia, 3: South Evvoikos Gulf, 4: Gavdos Island, 5: Zakynthos Island, 6: Kalamos Island, 7: Mytilini Island, 8: Kythira Island, 9: Rodos Island, 10: Karpathos Island, 11: Corfu Island, 12: Limnos Island, 13: Kyparissiakos Gulf, 14: Chios Island, 15: Bay of Tolo, 16: Skiathos Island, 17: Gerolimenas. 11

14 Data collection Available cetacean records have been systematically gathered between 1991 and 2008 and inserted in a database. Sources included dedicated surveys, opportunistic sightings, stranding reports from stranding networks, published or unpublished photographic and video documentation of strandings or sightings, historical strandings published in the scientific literature and skeletal materials. All records presented in a previous published review (Frantzis et al. 2003), sightings from a published article on cetaceans of the Aegean Sea (Carpentieri et al. 1999), and confirmed first-hand sightings found in the literature have also been included in the dataset. This dataset accounted for 2809 records; 1392 strandings and 1417 sightings. Surveys and sighting data Twenty six dedicated surveys were conducted during spring, summer or autumn (but predominantly in the summer) of each year, from 1991 to 2008 by the research teams of Pelagos Cetacean Research Institute (twenty two expeditions) and Tethys Research Institute (four expeditions). Surveys lasted from ten days up to three months and covered the Hellenic Trench, the Gulf of Corinth and in a lesser degree the Myrtoon Sea and the sea area between the Northern Sporades Islands and the Chalkidiki Peninsula (Figure 1). Ferries with standard routes were used as platforms of opportunity by Carpentieri et al. (1999) for their surveys in the Aegean and Cretan Seas. Conventional visual methods for detecting cetaceans have been used during the surveys. At least one experienced observer was continuously scanning the sea surface 180 in front of the vessel. Observers used intermittently binoculars and observations were interrupted when sea surface conditions reached 3 Beauforts (appearance of the first white caps). Geographic coordinates of the sightings were recorded with the aid of a Global Positioning System (GPS). Only the initial position of each sighting was considered, disregarding sighting duration or group-size changes, resulting in plots of one spot per sighting. Minimum distance from the closest coast and approximate bottom depth for all sightings were calculated a posteriori by GIS methods. In surveys along the Hellenic Trench, in the Northern Sporades Chalkidiki area and Myrtoon Sea, joint acoustic and visual methods were used. In those cases a stereo towed hydrophone array allowed passive acoustic localisation of sperm whales. Published or kindly offered sighting data from dedicated surveys of research teams that crossed the Greek Seas (mainly IFAW, GREC and Voyage of Odyssey) were also included in the dataset. Opportunistic sightings recorded up to the end of 2008 in the Greek Seas have also been included in the database, only when supported by photos or videos that allowed an unbiased species identification. 12

15 Sightings from the core study area of long-term studies on short-beaked common dolphins and common bottlenose dolphins in the inner east Ionian Sea (Bearzi et al. 2005, 2006) and the Amvrakikos Gulf (Bearzi et al. 2008a) have not been used, since their high numbers would create a very significant geographical unbalance in the dataset. Caution is due to the interpretation of the number of sightings recorded per species (Table 1) since data include both opportunistic sightings and results of dedicated surveys that used different methods (e.g. visual versus joint visual-acoustic surveys). Even more importantly, some areas have been surveyed intensively or more systematically than others (Annex I, Figure 2); others have not been surveyed at all. As a result the number of sightings recorded per species is not directly indicative of the relative sighting frequencies in this study and the relative presence/absence on the maps is not directly indicative of abundance. Stranding data Stranding data (including floating carcasses and incidentally caught animals) were obtained mainly through the national stranding network established by the Hellenic Centre for Marine Research in collaboration with the Port Police authorities. This network provided information to various recipients (ministries, research centres and NGOs) during the period By 2002 the available information started being centralised at the Ministry of the Marine Merchandise (YEN) from where copies of all records were obtained regularly. The network's data cover the period September 1991 December 2008, and derive from standardised forms filled by local Port Police authorities. This network can not keep track of all the stranding events and the number of unreported strandings some of which were incorporated to the dataset after becoming known through sources other than the network - is not negligible, particularly in the early years and the period The stranding records used in this report originated from two independent databases. The database of Pelagos Cetcean Research Institute contained 1263 records and the database of MOm (Hellenic Society for the Study and Protection of the Monk Seal) contained 342 records. The two databases were merged and duplicates were eliminated. Stranding data refer to number of animals stranded and not to multiple stranding events (strandings of three or more individuals were rare and concerned mainly Cuvier s beaked whales). The stranding data presented here may underreport smaller species, while large whales (mainly fin whales and sperm whales, which are conspicuous and account for exceptional events) were more likely to be reported. Since Port Police and local veterinarians may not possess the expertise needed to correctly identify cetacean species, all information coming 13

16 from the network was initially considered as suspect, except for the fact that a stranding did occur. After being meticulously checked, stranding reports were classified as unidentified cetaceans, unidentified delphinids (common bottlenose dolphins, striped dolphins or shortbeaked common dolphins) or unidentified small delphinids (small dolphins of 2.5 m total length or less, in advanced decomposition, having a rostrum and 35 or more teeth in one jaw, which could be either striped dolphins or short-beaked common dolphins) if the absence of visual documents (photos or videos) or their quality could not allow for reliable species identification. It has to be noted that Risso s dolphins are never reported by the Port Police as dolphins because of their different head shape, so they could not be part of the unidentified delphinids. Identification only took into account species known to occur in the Mediterranean Sea (Reeves & Notarbartolo di Sciara 2006). According to the above mentioned procedure, species identification was possible in 47% of the total stranding records. Unidentified animals were almost exclusively common bottlenose dolphins, striped dolphins and short-beaked common dolphins. This fact resulted in important underestimation of the percentage of these species among identified strandings (Table 1). In order to overcome this problem and reach a better approximation of the real figures, we split the categories of a) unidentified delphinids to common bottlenose dolphins, striped dolphins and short-beaked common dolphins according to the ratio 207:138:52 found among 397 identified stranded dolphins from 1996 to 2008 (Table 1), and b) unidentified small delphinids to striped dolphins and short-beaked common dolphins according to the ratio 138:52 found among 190 identified stranded dolphins of these two species from 1996 to 2008 (Table 1). This thirteen-year period was selected for two reasons: i) there were no strandings for each of these three dolphin species and for each year before 1996, ii) the ratio among these species strandings before 2006 was altered in favour of striped dolphins due to the Mediterranean morbillivirus epizootic, which peaked in 1992 in Greece (Aguilar and Raga 1993, Cebrian 1995, Aguilar 2000). Except for calculating new percentages for the occurrence of the small delphinid species among strandings from 1996 to 2008 (Table 1), the results of the above extrapolation were not used for any other purpose (e.g. distribution maps). Thirty eight old and historical stranding records from the period August 1991 were also included in the database since they were accompanied by photos or cited in scientific references (De Heildreich 1878, Bauer 1978, Kinzelbach 1986a, 1986b). The gender of stranded animals was included only after direct examination or when good photos of the genital area were available. Total lengths were retained only if measured by specialists or by local authorities instructed by experienced cetologists. 14

17 INFORMATION FROM CETACEAN RECORDS Recorded species Eleven cetacean species have been identified in a total of 1416 sightings and 1392 stranded animals recorded in the Greek Seas (Table 1). Six of these species were observed yearround in all or many of the Greek Seas: striped dolphin (Stenella coeruleoalba), common bottlenose dolphin (Tursiops truncatus), short-beaked common dolphin (Delphinus delphis), Cuvier's beaked whale (Ziphius cavirostris), sperm whale (Physeter macrocephalus) and Risso's dolphin (Grampus griseus). A seventh species, the harbour porpoise (Phocoena phocoena), was also observed year-round, but due to the low number of records more data are needed to allow a definitive confirmation of year-round presence. One more species, the fin whale (Balaenoptera physalus), has been recorded during all seasons in both sighting and stranding data. However, based on the available information its presence in winter and spring may be either regular or occuring exceptionally in some years only. The remaining three species - humpback whale (Megaptera novaeangliae), false killer whale (Pseudorca crassidens) and common minke whale (Balaenoptera acutorostrata) - have rarely been recorded in the Greek Seas. Table 1: Number of sightings and stranded animals per cetacean species. The unidentified delphinids concern the species Tursiops truncatus, Stenella coeruleoalba and Delphinus delphis. The unidentified small delphinids concern the species S. coeruleoalba and D. delphis. Most of the unidentified cetaceans were probably specimens of Grampus griseus according to the reported information, but no photos were available. For the estimation of the extrapolated results (marked with asterisks) in the last two columns, see methodology in section Stranding data. Species Sightings Total stranded animals Aug Stranded animals Sept Extrapolated Stenella coeruleoalba % * 31.2% * 2 Tursiops truncatus % * 44.8% * 3 Delphinus delphis % * 11.7% * 4 Ziphius cavirostris % % 5 Physeter macrocephalus % % 6 Grampus griseus % % 7 Balaenoptera physalus % % 8 Phocoena phocoena % % 9 Pseudorca crassidens % Megaptera novaeangliae % % 11 Balaenoptera acutorostrata % % Total identified % * 99.5% * Unidentified cetaceans % % Unidentified delphinids % 444 0* 0.0% * Unidentified small delphinids % 18 0* 0.0% * Total % % 15

18 Distribution and effort The distribution of all available records (Figure 3, Annex II) provides a reasonably good coverage of the Greek Seas and therefore, the geographic range given for each species is thought to represent a good approximation of the real figures. Nevertheless, much more effort is needed in order to obtain the precise distribution of each species. The absence of sightings in some geographical areas is in most cases the result of lack of survey effort (e.g the central and eastern Aegean). However, in some particular areas (Patraikos Gulf and inner Ionian Sea) the absence of sightings more accurately reflects the scarcity of cetacean presence. Figure 2 in Annex I provides the distribution of the searching effort so far and it is particularly useful in avoiding misinterpretation of the results of this report, as well as for planning future research effort. The cetacean species recorded in the Greek Seas can be divided in three major categories according to their distribution: a) the striped dolphin, the common bottlenose dolphin, the sperm whale and the Cuvier s beaked whale are or seem to be present in the entire range of the bathymetry/habitat that is considered typical for them, b) the short-beaked common dolphin, the fin whale and the harbour porpoise present heterogeneous distributions within their potential habitats, c) the Risso s dolphin can be predictably found in a small number of areas only, although its occurrence (as sightings or strandings) has been recorded in most geographical areas of the Greek Seas. Stranding data Eleven species have been identified within the stranding record (Table 1). The percentage of identified animals among 1352 strandings from 1991 to 2008 was 47%. As the vast majority (99%) of unidentified animals belonged almost exclusively to three delphinid species (common bottlenose dolphins, striped dolphins and short-beaked common dolphins), their percentages among identified animals are underestimated. Extrapolated numbers for these three species (see methods in section Stranding data ) for the period are presented in Table 1. The common bottlenose dolphin is the most common species among strandings (44.8%) followed by the striped dolphin (31.2%). Averages of ca. 34 and 23 stranded animals per year were recorded for these two dolphin species, respectively. The short-beaked common dolphin was found among strandings with an average rate of 9 stranded animals per year (11.7%). The occurrence of Cuvier s beaked whale (5.5%) in the stranding record accounted for about four animals per year, but when atypical mass strandings were excluded this number was about two per year. The Risso s dolphin (2.2%), the sperm whale (1.7%) and the harbour porpoise (1.5%) accounted for 16

19 about 1 to 1.5 strandings per year. Finally, the fin whale, the humpback whale and the common minke whale represented rare stranding events (less than 0.5% of the total strandings each). Mass strandings were relatively rare. Twenty-nine strandings involving more than one animal (couples, mass strandings sensu Geraci and Lounsbury 1993, or atypical mass strandings as described in Frantzis 1998) have been recorded during the period September 1991 December Two previous mass strandings of four Cuvier s beaked whales each have been recorded in 1987 and In 31 stranding events involving more than one individual, twelve cases (39%) concerned Cuvier s beaked whales, four cases (13%) concerned striped dolphins, one case concerned sperm whales, one case (entanglement) concerned striped dolphins and a Risso s dolphin, one case concerned common bottlenose dolphins and twelve cases (39%) concerned unidentified delphinids. The atypical mass stranding of fourteen Cuvier s beaked whales in 1996 was linked with the use of military sonar during exercises (Frantzis 1998). Another atypical mass stranding of nine Cuvier s beaked whales in 1997 could also be due to similar causes (Frantzis 2003). At least in two cases striped dolphins and unidentified small delphinids bore obvious anthropogenic wounds (inflicted by knives). In two other cases three dolphins were found dead in neighbouring sites of the same coast during the same day; an indication that they were either killed intentionally or by-caught. In the first case these were two short-beaked common dolphins and one unidentified small delphinid. In the second case all three dolphins were unidentified, but heir sizes (2.65, 2.80 and 2.90 m) suggest that they were probably common bottlenose dolphins since common dolphins and striped dolphins do not reach such lengths in the Mediterranean Sea (Notarbartolo di Sciara 1997, Aguilar 2000, Bompar 2000). All these cases concern strandings which involved more than one individual of dolphins bearing anthropogenic wounds. Many cases of single dolphins with signs of intentional killing have been reported, but most of them were impossible to confirm or reject due to the the low quality or the absence of photos. In at least two cases, striped dolphins stranded alive and showed behavioural symptoms similar to those presented by dolphins infected by the Mediterranean morbillivirus. No detailed data are available for the rest of strandings that involved more than one individual. 17

20 Sighting data Ten cetacean species (all but the minke whale) have been sighted in the Greek Seas (Table 1). Two dolphin species, the striped dolphin (36.9%) and the common bottlenose dolphin (21.6%) accounted for more than half of the total number of sighting records. Dedicated sperm whale surveys (joint acoustic and visual methods) resulted in a relatively high percentage of sightings for this species (21.1%). Sightings of short-beaked common dolphins and Cuvier s beaked whales were less frequent (9.9 and 4.9%, respectively); sightings of fin whales and Risso s dolphins were relatively rare (2.7 and 2.5%, respectively). Finally, sightings of humpback whales, false killer whales and harbour porpoises were very rare and occurred twice for humpback whales (single anumals) and once for the other two species. If we consider only the surveys made in the pelagic waters and near the continental slope, the striped dolphin was the most frequently observed species, followed by the sperm whale, the Cuvier s beaked whale, the Risso s dolphin and the fin whale. Above the continental shelf, the common bottlenose dolphin was the most frequently observed species followed by the short-beaked common dolphin. 18

21 SUMMARIZED INFORMATION FOR ALL COMMON SPECIES Table 2: Summary of information on the eight cetacean species that are regularly found in the Greek Seas. *Proposed IUCN Red List classification (Reeves & Notarbartolo di Sciara 2006) Species English common name 1 Balaenoptera physalus Fin whale 2 Physeter macrocephalus Sperm whale 3 Ziphius cavirostris 4 Grampus griseus 5 Tursiops truncatus 6 Stenella coeruleoalba 7 Delphinus delphis 8 Phocoena phocoena Cuvier s beaked whale Risso s dolphin Common bottlenose dolphin Striped dolphin Short-beaked common dolphin Harbour porpoise Greek common name Type Depth Pelagic, occasionally coastal Slope, secondarily pelagic Slope, probably pelagic as well Slope, probably over its shallower part Typically coastal, also over shallow waters offshore Typically pelagic and slope Coastal and shallow, ( pelagic and deep only in the Gulf of Corinth) Probably coastal and shallow Habitat IUCN Status Geographic distribution Main threats Mediterranean* Globally 81 m (coastal) 670 m ( m) 1235 m ( m) 1066 m ( m) 737 m ( m) 121 m ( m) 1024 m ( m) 86 m ( m) Gulf of Corinth: 713 m ( ) Distance from coasts 2.9 km (coastal) 14.7 km ( km) 8.1 km ( km) 8.6 km ( km) 8.2 km ( km) 3.0 km ( km) 8.7 km ( km) 4.3 km ( km) Gulf of Corinth: 5.9 km ( ) Present in N Ionian Sea and especially from NW of Lefkada Island north up to N Corfu; at least occasionally in Saronikos Mainly along the Hellenic Trench from Kefallonia to E Rodos, also in deep basins/trenches of the Aegean Sea (Myrtoon, Cretan, N Ikarion, NW Aegean Sea) Present and locally (S Crete, W Lefkada) common all along the Hellenic Trench; present or common over steep depressions of the Aegean (e.g. N. Sporades) Common in Myrtoon Sea south to NW Crete, present or common in N. Sporades and Chalkidiki, present or rare or seasonal in all other Aegean and Ionian Seas Present in all coastal areas, straits, gulfs, and also between islands in the entire Ionian, Aegean and Cretan Seas with no exceptions. Common in all areas over depths >500 m (present in >200 m) including Gulf of Corinth. Absent/vagrant in depths <200 m. Thracian Sea, Thermaikos Gulf, Northern Sporades, Pagasitikos Gulf, NE Aegean Sea, Cyclades; S Evvoikos Gulf, Dodecanese; Gulf of Corinth, Inner Ionian Sea, recorded in N Evvoikos Gulf Thracian Sea, possibly present in - - Thermaikos Gulf and Chalkidiki peninsula. Only vagrant further to the south. Ship strikes in the western Mediterranean Ship strikes Noise Plastic debris Sonar Noise Plastic debris Bycatch in long-lines Plastic debris Prey depletion Direct killing Bycatch in artisanal fishery Noise Chem. pollution Direct killing Bycatch in driftnets Prey depletion Direct killing Bycatch in artisanal fishery Climate change Bycatch in artisanal fishery Prey depletion? Details (in page) Data deficient Endangered 23 Endangered Vulnerable 27 Data deficient Data deficient Least concern Least concern Vulnerable Vulnerable 39 Vulnerable Endangered Endangered Least concern Least concern Least concern

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23 CETACEAN SPECIES COMMONLY OCCURRING IN THE GREEK SEAS Drawings by Massimo Demma / ICRAM 21

24 22

25 Balaenoptera physalus (Linnaeus, 1758) Fin whale Scientific name: Balaenoptera physalus Common name: Πτεροφάλαινα Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Pterofálaina pterofálena Taxonomy Order: Suborder: Family: Subfamily: Genus: Species: Cetacea (Κητώδη) Mysticeti (Μυστακοκήτη) Balaenopteridae (Φαλαινοπτερίδες) Balaenopterinae (Φαλαινοπτερίνες) Balaenoptera Balaenoptera physalus Relevant common names EN fin whale AR (harcul chaii) FR rorqual commun TR uzun balina ES rorcual común AL balene kokemadhe IT balenottera comune HR veliki kit DE Finnwal HE (livyatan matzui) PT baleia-comum ML baliena mbaðða Size The available information on body size of fin whales of the Mediterranean population, part of which are those visiting the Greek Seas, is coming from 103 stranded specimens in the period (Notarbartolo di Sciara et al. 2003). The maximum total length of Mediterranean fin whales is above 20 m; probably somewhere between 21 and 23 m. Because almost all stranded whales that were 20 m were reported as approximately 20 m and most of them originate from the 19 th century, no precise measurements of large specimens are available. The mean total length form strandings is 13.8 m. Females may be slightly larger than males and total length at birth is probably close to 5.2 m. The total length of measured fin whales that stranded along the Greek coasts range between m, but skeletal remains of one specimen indicate a total length of approximately 20 m. 23

26 Reported sightings and strandings There are 36 sightings of fin whales recorded in the Greek Seas, most of them (31) originating from the north Ionian Sea and Saronikos Gulf. Three of the sightings in the inner Ionian Sea concerned the same individual. The sightings in Saronikos Gulf were all made in two different years within periods that spanned five and two months. Fin whale strandings are relatively rare in Greece (ten in total) and only half of them have been recorded after 1991 (Table 1). Geographic range The fin whale seems to be predictably present off the northern Ionian Islands and particularly northwest of Lefkada Island. Four sightings and four strandings were recorded further to the south along the Hellenic Trench. Fin whales seem to be rare in the Aegean Sea, but they were repeatedly reported in the Saronikos Gulf in 1998, 2006 (stranding) and Fin whales may visit, regularly or occasionally, specific areas of the Aegean Sea during winter or spring, when prey abundance may be suitable to their needs. Single individuals and small groups of up to three or four fin whales were observed repeatedly in Saronikos Gulf in the spring of 1998 and 2008, and one stranding was recorded in spring Exceptional near-coast observations were made in the western Mediterranean Sea during summer and autumn 1997, and were related to particular oceanographic conditions (Beaubrun et al. 1999; Notarbartolo di Sciara et al. 2003). Apparently regular winter presence (January to March) close to the coasts was reported in Lampedusa Island (Italy) and has been related to feeding (Canese et al. 2006). Except for sightings in Saronikos Gulf, all other sightings in the Greek Seas come from the warm season from June to September when most of the search effort occurs. Fin whales have been occasionally observed to wander in shallow coastal waters (south Peloponnese) or enclosed sea areas like the inner eastern Ionian Sea. The single presence of a fin whale in the closed Gulf of Corinth was a case of a wandering animal that apparently died later in this gulf. Habitat Fin whales in the Mediterranean appear to be markedly pelagic. They are primarily observed in deep (over 2000 m) offshore waters, although their occurrence over the continental slope or the continental shelf is not unusual (Notarbartolo di Sciara et al. 2003). The mean water depth from 15 fin whale sightings made in the open Ionian Sea was only 670 m (sd=398) and the mean distance from the coasts was 14.7 km (sd=6.2). These values are certainly underestimates of the real figures, since they occurred while surveying areas relatively close to the coasts. However, there are 17 sightings made in the inner Greek Ionian Sea, the south Peloponnese and Saronikos Gulf showing presence in even shallower and more coastal waters over the continental shelf or even in closed gulfs and bays. Their mean water depth and distance from the coasts are 81 m (sd=50) and 2.9 km (sd=2.8), respectively. This strong variability in habitat characteristics may be due to year-to-year differences in oceanographic conditions and therefore, variable distributions and densities of the fin whales principal prey in the Mediterranean (Notarbartolo di Sciara et al. 2003). It is noteworthy that all fin whale records in Saronikos Gulf occurred in early spring, in three different years. At least during the last time (in 2008), the sightings coincided with very high densities of krill in the gulf (personal observations). 24

27 Abundance The fin whales that visit the Greek Seas seem to be a small part of the Mediterranean fin whale population and it is probably meaningless to try to guess a size for the Greek population unit. Even if such a number could be estimated or guessed, it is reasonable to think that it would be variable from year to year, since the known range of the species in the Greek Ionian Sea is limited and its presence in Saronikos Gulf or the entire Aegean Sea is apparently variable. There is no population estimation for the entire Mediterranean Sea, (Notarbartolo di Sciara & Panigada 2006). The best guess for the entire Mediterranean population would be in the low thousands, as an extrapolation from estimates of abundance for the western basin that varied between roughly 1000 and 3500 animals (Forcada et al. 1995, 1996). Probably few tens up to very few hundreds among them are found in or visit yearly the Greek Seas. Population trend The Mediterranean population trend is completely unknown and no time series of sighting frequencies exist for the fin whales visiting the Greek Seas. Degree of residency and/or isolation The seasonality of observations in Saronikos Gulf may be suggestive of seasonal migrations that are well known for the Mediterranean fin whale population (Notarbartolo di Sciara et al. 2003). There is no evidence in favour or against a single, panmictic population in the Mediterranean or a metapopulation comprised of a number of subunits. No genetic study has been made on fin whale from the Greek Seas. Genetic analyses showed that the Mediterranean fin whales are largely resident in the basin, although limited but recurrent gene flow occurs through the Straits of Gibraltar (Bérubé et al. 1998, Palsbøll et al. 2004), and satellite tagging confirmed these findings (Guinet et al. 2005). Seasonality of reproduction No data are available from the Greek Seas and no neonates were found among strandings. According to data from the western Mediterranean, the frequency of occurrence of neonates is higher between September and January, with a peak in November, but births may occur throughout the year in the Mediterranean (Notarbartolo di Sciara et al. 2003). Feeding habits Unknown in the Greek Seas, but the seasonal coincidence of fin whales with concentrations of krill in Saronikos Gulf (personal observations) and the observations of bright orange, football-sized floating feces of fin whales in the eastern Ionian Sea (Notarbartolo di Sciara et al. 2003) are both indicative of krill feeding. Krill is known to be the main fin whale prey in the Ligurian-Corsican-Provençal Basin during summer, but feeding on epipelagic fish may also occur in other locations of the Mediterranean (Notarbartolo di Sciara et al. 2003). 25

28 Main threats In the western Mediterranean ship strikes constitute the main known source of anthropogenic mortality for fin whales. Shipping noise and vessel disturbance, particularly from the unregulated whale watching, is another source of concern (Notarbartolo di Sciara & Panigada 2006). No information is available on threats to fin whales in the Greek Seas. IUCN Red List classification Mediterranean subpopulation proposed as Data Deficient (Notarbartolo di Sciara & Panigada 2006); listed as Endangered globally (IUCN 2008). 26

29 Physeter macrocephalus (Linnaeus, 1758) Sperm whale Scientific name: Physeter macrocephalus Common name: Φυσητήρας Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Fysitíras fysitíras Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Physeteroidea (Φυσητηροειδή) Family: Physeteridae (Φυσητηρίδες) Genus: Physeter Species: Physeter macrocephalus Relevant common names EN sperm whale AR (anbar) FR cachalot TR kačalot ES cachalote AL kashalot IT capodoglio HR ulješura DE Pottwal HE (roshtan) PT cachalote ML gabdoll Size The largest female stranded in Greece was 10.0 m long and the maximum total length measured acoustically (Gordon 1991) for female sperm whales is 9.1 m (Pelagos Cetacean Research Institute, unpublished data). The largest male measured acoustically was 14.6 m (Frantzis & Alexiadou 2008). However, the lower jaw bone of a stranded male indicates a total length between 15.5 and 17.5 m (Pelagos Cetacean Research Institute, unpublished data). The maximum total length recorded for Mediterranean female and male sperm whales is approximately 10.5 m and 17.3 m, respectively (Cagnolaro 1996, Centro Studi Cetacei 1997). The smallest stranded animal in Greece was 4.0 m long, and although its decomposition state did not allow a definitive conclusion, it did not seem to be a neonate. Size at birth ranges globally for sperm whales between 3.5 and 4.5 m (Best et al. 1984). 27

30 Reported sightings and strandings There are 300 sightings of sperm whales recorded in the Greek Seas, most of them (274) recorded along the Hellenic Trench, mostly in the framework of dedicated surveys in this area. During the last decade sperm whale strandings occurred along the Greek coasts at the rate of approximately 1.5 whales per year. The total record includes 26 strandings, of which 19 recorded after 1991 (Table 1). Geographic range The existence of a deep trench all around Greece (the Hellenic Trench) as well as smaller steep depressions and trenches in the Aegean Sea (Figure 1) make the Greek Seas an important habitat for sperm whales, both solitary males and social units. Sperm whales are present year-round along the Hellenic Trench, most sightings being recorded from SW Kefallonia Island south to W Peloponnese, W and S Crete. Their presence along the Hellenic Trench continues north-eastern to Karpathos Island and E Rodos Island in the Levantine Sea. Sperm whales can also occur in the Myrtoon Sea, Cretan Sea, N Ikarion Sea and all steep depressions of the Aegean Sea, particularly in the area between the Northern Sporades and the Chalkidiki Peninsula. Several strandings and one sighting in the shallow Cyclades Islands area that has not been surveyed sufficiently yet indicate that sperm whales may cross it while moving from one area of steep underwater relief to another. Sperm whales are also present in further offshore waters off the Hellenic Trench, although their abundance appears to decrease at greater distances from the trench (Frantzis et al. in preparation). Habitat Sperm whales occupy both the continental slope and pelagic habitats in the Greek Seas, although their abundance is higher along the continental slope (Frantzis et al. in preparation). Occasionally, they may be found over the continental shelf, since they enter the Aegean Sea plateau to reach deep basins or trenches in the north Aegean. The mean water depth and distance from the coasts of 188 sperm whale sightings made along the Hellenic Trench was 1235 m (range m; sd=426) and 7.9 km (range km; sd=4.9), respectively. These values may be representative only for sperm whales along the continental slope, since the available sightings far offshore over the abyssal plains (pelagic habitat) are extremely few. The year-round presence of both mature males and social groups of females with young calves across the Hellenic Trench highlights the extraordinary importance of this habitat for the protection of the Mediterranean population of this species. Abundance There is no estimate of abundance for the entire sperm whale population of the Mediterranean Sea, however, a guess of regional specialists place it closer to the mid hundreds than the few thousands (Notarbartolo di Sciara et al. 2006). There is a recent estimation for the entire Ionian Sea (including international and Italian waters) that accounts for 62 individuals (Lewis et al. 2008). This may be an underestimate of the real figures since the relevant surveys did not consider the Hellenic Trench as a separate stratum, did not account for non-vocalizing animals (calves or resting individuals) and may have 28

31 underestimated the total number of individuals clustered in social units (the survey track just crossed them, without additional effort in counting them with joint acoustic/visual methods), as acknowledged by the authors. During eleven years of research on sperm whales of the Greek Seas, 166 individuals have been photo-identified so far, and the first rough estimations indicate a total close to 200 individuals that live along or cross the Hellenic Trench (Pelagos Cetacean Research Institute unpublished data). Considering that some of the individuals observed in the Aegean Sea were also photo-identified in the Hellenic Trench, the entire sub-population of sperm whales living in the Greek Seas is unlikely to exceed 300 animals. Population trend The population trend of Mediterranean sperm whales is not clearly known, but the available evidence and the high number of individuals removed by driftnet fisheries are consistent with the hypothesis of a marked decline (Notarbartolo di Sciara et al. 2006). The Greek subpopulation is also thought to be decreasing since the suspected mortality rate from only one anthropogenic cause, namely collisions with large vessels as indicated by propeller marks on the body of stranded sperm whales, seems too high to be sustainable (Pelagos Cetacean Research Institute unpublished data). Degree of residency and/or isolation Resightings of photo-identified individuals on an almost yearly basis from 1998 to 2008 indicate that sperm whales are at least seasonally resident in the Greek Seas, and may spend many years of their life in the Greek Seas or close to them (Frantzis et al. in preparation). Occasional observations revealed that individuals captured photographically during the summer/autumn season are also present along the Hellenic Trench during winter (Pelagos Cetacean Research Institute, unpublished data). There are no data regarding the degree of isolation between the sperm whales of the eastern and western Mediterranean basins. It has to be noted that coda comparisons indicated that such isolation is possible (Rendel et al. 2007). In addition, no photo-identification matches have been made so far between individuals in the two basins (NAMSC, DELPHIS, CIRCE, Tethys Research Institute and Pelagos Cetacean Research Institute databases). Nevertheless, mt-dna and microsatelite genetic comparisons have clearly shown that the Mediterranean sperm whale population differs significantly from the Atlantic one (Engelhaupt et al. submitted) Seasonality of reproduction Observations of 9 newborns and 3 stranded young calves indicate that most births occur from mid June to end of August with a peak in July, although some births may occur in late winter to early spring (Pelagos Cetacean Research Institute unpublished data). Feeding habits Prey items in the stomach content of five sperm whales stranded in Greece only included squids and squid remains (Pelagos Cetacean Research Institute unpublished data). One 29

32 published stomach content contained the remains of seven cephalopod species, Histioteuthis bonnellii being the dominant one (Roberts 2003). Main threats Although mortality in pelagic driftnets appears to be the most likely cause of recent decline for sperm whales at the Mediterranean level (Notarbartolo di Sciara et al. 2006), ship strikes seem to be the most important threat for the species in the Greek Seas. Almost two out of three sperm whales stranded in Greece bear marks of collision with a large vessel (Pelagos Cetacean Research Institute, unpublished data). Ingested plastic debris (found in three of five stomach contents; unpublished data) and underwater noise from seismic surveys, military operations, and illegal dynamite fishing (still common in sperm whale habitat; Frantzis et al. 2003) are other sources of concern (Notarbartolo di Sciara & Gordon 1997). IUCN Red List classification Mediterranean subpopulation proposed as Endangered (Notarbartolo di Sciara et al. 2006); listed as Vulnerable globally (IUCN 2008). 30

33 Ziphius cavirostris G. Cuvier, 1823 Cuvier s beaked whale Scientific name: Ziphius cavirostris Common name: Ζιφιός Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Zifiós zifjós Taxonomy Order: Cetacea (Κητώδη) Suborder: Suprafamily: Ziphioidea (Ζιφιοειδή) Family: Ziphiidae (Ζιφιίδες) Subfamily: Ziphiinae (Ζιφιίνες) Genus: Ziphius Species: Ziphius cavirostris Odontoceti (Οδοντοκήτη) Relevant common names EN Cuvier s beaked whale AR (zifius) FR ziphius TR Kuvier balinasi ES zifio de Cuvier AL baleen me sqep IT zifio HR Cuvierov kit DE Cuvier schnabelwal HE (zifyus chalul chartom) PT zifio ML baliena ta Kuvjer Size Information on the body size of Cuvier s beaked whales in the Mediterranean Sea originates from stranded animals and clearly indicates smaller sizes than those observed in the oceans where animals larger than 6 m are recorded. The average size for both sexes globally is 6 m and the largest reliably measured individual was 6.93 m according to Heyning (1989). However, the largest Cuvier s beaked whales recorded in the Mediterranean were 7.6 m (a female; Casinos & Vericad 1976) and 6.3 m (Duguy 1985). These measurements are much longer than the third and fourth longer available ones (5.8 and 5.70 m; Centro Studi Cetacei 1995, 1996). The largest specimen measured in Greece was a male 5.32 m long, bearing erupted small teeth. The total length at birth globally is 2.7 m (Heyning 1989). However, a 2.20 m individual stranded in Greece does not seem to be an aborted fetus based on the available photos, suggesting that size at birth may be smaller. 31

34 Reported sightings and strandings There are 70 sightings of Cuvier s beaked whales recorded in the Greek Seas, mostly (66) in the Hellenic Trench. Cuvier s beaked whale strandings (100 in total) and sightings were common in the Greek Seas until recently (Table 1), but became suspiciously rare during the last years. Cuvier s beaked whales are the only cetacean species of the Greek Seas found stranded in groups of 2-4 individuals due to either natural or anthropogenic causes. Cuvier s beaked whales have mass stranded twice in high numbers (at least 14 and 9 individuals). At least one of these cases was due to the use of military sonar (Frantzis 1998, 2004). Geographic range In the Greek Seas Cuvier s beaked whales seem to have a quite similar geographic range (with slight differences) to that of the sperm whale. Although present all along the Hellenic Trench from NW Corfu to E Rodos Island, the only known areas where this species can be predictably observed is the area of S Crete and W Lefkada. In addition, the Cuvier s beaked whale seems to be present over steep depressions of the Aegean plateau (strandings in Chalkidiki, N Limnos, Ikarion Sea, S Milos Island and Karpathos Island), although observations are available only for the sea area north of the Northern Sporades and one for the Cretan Sea. It is not known if Cuvier s beaked whales are also present further offshore, over the abyssal plains, although this seems probable according to other observations in the far offshore Ionian (J. Forcada in litteris) and west Mediterranean Sea. Very few strandings were recorded away from steep depressions and deep trenches and no sightings were made above the shallow waters of the continental shelf and the enclosed gulfs, where the Cuvier s beaked whales are apparently absent. Habitat The Cuvier s beaked whales occupy the continental slope and possibly pelagic waters as well in the Greek Seas. The mean water depth and distance from the coasts of 63 Cuvier s beaked whale sightings made along the Hellenic Trench was 1066 m (range m; sd=343) and 8.6 km (range km; sd=6.1), respectively. These values should be considered representative only for Cuvier s beaked whales along the slope or above the Aegean plateau, since there are no available sightings farther offshore over abyssal plains. Important Cuvier s beaked whale habitat seem to exist in portions of the Greek Seas that are among the very few areas known in the Mediterranean Sea where this species was or perhaps still is reasonably abundant (Frantzis et al. 2003, A. Cañadas, pers. comm.). Such habitats have a high conservation value for the Mediterranean population of this species, and therefore, would warrant conservation action. Abundance The available data do no allow estimating population abundance. Cuvier s beaked whales are elusive animals difficult to observe or to detect acoustically. There are no population estimates anywhere in the Mediterranean Sea. 32

35 Population trend While abundance trends remain unknown, a decrease in sightings and strandings (with no reduction in search effort) during the last decade raises concern over a possible population decline. Two mass stranding events removed a relatively high number of individuals (at least 23) from local populations, but the total number of animals that died without reaching the coasts may have been much higher. The impact at the population level seems important, but could potentially be even dramatic. Degree of residency and/or isolation The stranding records cover all months of the year and indicate year-round presence in the Greek Seas. No studies have been conducted to elucidate the degree of residency of particular individuals or groups. Genetic studies on mt-dna showed that the Mediterranean (represented by ten samples from Greece and two from Croatia) was highly distinct from the neighbouring Eastern North Atlantic. Haplotype diversity was also lower in the Mediterranean than in other regions, suggesting that this population could be both isolated and relatively small. The eastern Mediterranean population, in particular, was suggested to represent a separate evolutionarily significant unit (Dalebout et al. 2005). Seasonality of reproduction The smallest calf (2.20 m) found in Greece stranded in late June. Four calves ranging between 3.2 and 3.5 m were found stranded in November or early December. The only observation of a free-ranging young calf occurred in July. These data (Pelagos Cetacean Research Institute, unpublished data) indicate that most births should occur during early or mid summer. Feeding habits Based on the available stomach contents, Cuvier s beaked whales feed exclusively or mainly on mesopelagic and bathypelagic squids. Only squid remains were found in seven stomachs of animals that mass stranded in the W Peloponnese (Hellenic Trench). The analysis of a small number of squid beaks from these stomachs revealed the presence of three species: Histioteuthis bonnellii, H. reversa and Octopoteuthis sicula (Lefkaditou & Poulopoulos 1998). These species are also prey items of sperm whales in Greece (Roberts 2003). Similarly, one more stomach from a stranded individual contained only squid remains and a large number of squid beaks that remain to be identified (A. Frantzis, unpublished data). Stomach contents from other Mediterranean areas also contained only squid remains from nine mesopelagic and bathypelagic species (Blanco et al. 1997). Main threats The most important threat for this species is likely anthropogenic noise, responsible for significant mortality in Greece and the Mediterranean Sea in general. Military sonars and possibly high-energy sounds from other anthropogenic sources have repeatedly resulted in 33

36 the stranding and death of several Cuvier s beaked whales (Frantzis 1998, Jepson et al. 2003, Fernández et al. 2005). The impact of such mortality at the population level is uncertain, but there is increasing evidence indicating that it may be localy important. Another source of concern is the ingestion of plastic debris by Cuvier s beaked whales. Two stranded animals in Greece had stomachs full of pieces of plastic bags. IUCN Red List classification Mediterranean subpopulation proposed as Data Deficient (Cañadas 2006); listed as Vulnerable globally (IUCN 2008). 34

37 Grampus griseus (G. Cuvier, 1812) Risso s dolphin Scientific name: Grampus griseus Common name: Σταχτοδέλφινο Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Stachtodélfino staxtoðélfino Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Grampus Species: Grampus griseus Relevant common names EN Risso s dolphin AR (ghrambous) FR dauphin de Risso TR grampus ES calderón gris AL ; IT grampo HR dobri dupin DE Rundkopfdelphin HE (grampus) PT grampo ML denfil griú Size The Risso s dolphin is the largest dolphin species regularly occurring in the Greek Seas. The average total length form 20 stranded specimens measured in Greece is 2.92 m (sd=0.45). The maximum total length is 3.30 m and the minimum 1.73 m. The longest precisely measured known specimen in the Mediterranean Sea was 3.51 m (Centro Studi Cetacei 1995). The average length world-wide is 3.5 m, the maximum is 4.09 m and length at birth ranges between 1.1 and 1.5 m, no differences being observed between sexes (Kruse et al. 1999). 35

38 Reported sightings and strandings There are 38 sightings of Risso s dolphins recorded in the Greek Seas, mainly spread all over the Aegean Sea. All the sightings in the Gulf of Corinth concern repeated observations of the same two photo-identified individuals. Strandings of Risso s dolphins are not rare in Greece, although much less frequent than those of all other resident dolphin species (Table 1). The 34 strandings reported here are spread homogeneously in the Ionian, Aegean and Cretan Seas. Geographic range The distribution of the recorded sightings and strandings of Risso s dolphins in the Greek Seas seems to be homogeneous and indicates that the species may be present in all parts of the Greek Seas. However, there is only one known area where Risso s dolphins can be predictably found and this is the Myrtoon Sea south to the NW Crete. The sightings made in SW Crete come from the years 1998 and 1999, but despite the continuous effort no other sightings were made in this area until the end of The sightings in the Gulf of Corinth all come from the same two photo-identified individuals first observed in 1997 (Frantzis & Herzing 2002). Two other areas where sightings and strandings have been recorded are the Northern Sporades and the sea area of the Chalkidiki Peninsula. Surprisingly, no Risso s dolphins have been observed in the Ionian Sea, despite intense survey effort during more than a decade. However, the species occurs in the area, since nine strandings (two of which were live animals) have been recorded from the N Corfu to S Peloponnese. Apparently the species is present in low numbers or out of the warm season, when all the survey effort is concentrated. Eight strandings in the Ionian Sea have been recorded from the end of September to late April, and one in June. Sightings and strandings of Risso s dolphins have also been recorded in the relatively shallow area of the Cyclades Islands. Habitat Risso s dolphins have been observed mainly in the slope habitat, but also close to the coast and over the Aegean plateau, like in the Cyclades. This explains why the average depth of observations is less than that of sperm whales and the Cuvier s beaked whales. This is also due to the fact that the depressions in the Aegean Sea (where many of the sightings come from) have shallower depths than along the Hellenic Trench (where few observations are available for this species). The mean water depth and distance from the coasts of 37 Risso s dolphin sightings is 737 m (range m; sd=380) and 8.2 km (range km; sd=5.8), respectively. It is probable that Risso s dolphins are present farther offshore, over the abyssal plains, at least in the Levantine Sea (Song of the Whale Research Team 2007). In the western Mediterranean Risso s dolphins show a preference for deep pelagic waters, in particular over steep shelf slopes and submarine canyons (Gaspari and Natoli 2006, Azzelino et al. 2008). Abundance There are no available data on the abundance of this species in the Greek Seas. The stranding and sighting numbers indicate that it is much less abundant than striped dolphins, common bottlenose dolphins and short-beaked common dolphins, and probably more 36

39 abundant than fin whales and harbour porpoises. No abundance estimates are available for the Risso s dolphins in the Mediterranean, except for a small zone covering km 2 off the Valencian coasts in Spain (Gómez de Segura et al. 2006), where the estimate was 493 animals. In all surveyed areas in the Western Mediterranean, encounter rates have been variable but generally low (i.e encounters per km; Gaspari and Natoli 2006). Population trend Population trends are unknown, both at the regional and local level. Degree of residency and/or isolation Information from strandings and sightings suggests that Risso s dolphins may be present in Greek waters year-round. However, they may be seasonal in the Ionian Sea, where strandings (including live animals) were recorded almost exclusively during the cold months (end September late April). Risso s dolphins in the Mediterranean Sea are genetically differentiated from those in the eastern Atlantic and some evidence exists of population structure within the Mediterranean (Gaspari et al. 2006). Seasonality of reproduction No data are available from the Greek Seas or the Mediterranean, and no neonates were included in the stranding record. A young animal of 1.73 m stranded in late November and another, approximately 1.7 m long, stranded in late June. A calf was observed at sea in mid August. Feeding habits The diet of Risso s dolphins is based on squid and occasional fish (Kruse et al. 1999). In two stomach contents from Greece there were several unidentified squids and squid remains, and one stomach contained the entire skeleton of a largehead hairtail Trichiurus lepturus about cm long. Only one squid beak was found in the stomach of a third Risso s dolphin that was apparently sick while observed for several days before it died and stranded. Main threats Entanglement in longlines or nets was the cause of death for at least four stranded animals. Bycatch in fishing gear has also been reported to occur elsewhere in the Mediterranean (Gaspari and Natoli 2006). The stomach of one adult that stranded alive was full of plastic debris. 37

40 IUCN Red List classification Mediterranean subpopulation proposed as Data Deficient (Gaspari and Natoli 2006); listed as Least Concern globally (Notarbartolo di Sciara et al. 2006, IUCN 2008). 38

41 Tursiops truncatus (Montagu, 1821) Bottlenose dolphin Scientific name: Tursiops truncatus Common name: Ρινοδέλφινο Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Rinodélfino rinoðélfino Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Tursiops Species: Tursiops truncatus Relevant common names EN common bottlenose dolphin AR (delphin kabir) FR grand dauphin TR afalina ES delfín mular AL delfin i madh IT tursiope HR dobri dupin DE Grosser tümmler HE (dolphinan yam hatichon) PT roaz corvineiro ML denfil geddumu qasir Size The common bottlenose dolphin is the second largest dolphin species regularly occurring in the Greek Seas after the Risso s dolphin. The average total length of 185 stranded specimens measured in Greece is 2.44 m (sd=0.55). The maximum total lengths for males and females are 3.30 and 3.20 m respectively, and the minimum is 1.10 m for a neonate bearing fetal folds. The longest specimens in the Mediterranean Sea were a male 3.38 m (Universitat de Barcelona 1994) and a female also 3.38 m (Centro Studi Cetacei 1996). The maximum length world-wide is 3.81 m and length at birth ranges between 1.03 and 1.28 m (Wells & Scott 1999). 39

42 Reported sightings and strandings There are 305 sightings of common bottlenose dolphins spread all over the Greek Seas. This species is by far the most common cetacean in the stranding record (Table 1), as almost half of all strandings (44.8% in the extrapolated data) belong to this species. The 234 strandings are also spread quite homogeneously all over Greece. Geographic range The distribution of the recorded sightings and strandings of common bottlenose dolphins in the Greek Seas is homogeneous and shows that the species is present in most or all portions of the Greek Seas. It is present in all coastal areas, straits and gulfs, but also between islands in the entire Ionian, Aegean and Cretan Seas. The common bottlenose dolphin is the only cetacean species present in the shallow and enclosed Amvrakikos Gulf with an important and possibly isolated population unit (Bearzi et al. 2008a), and it is also present in the North and South Evvoikos Gulfs (Zafeiropoulos & Merlini 2001). It is also present along steep coasts with no continental shelf along the Hellenic Trench, although less common in comparison with shallow areas and plateaux. Habitat The common bottlenose dolphin occupies the continental shelf in the Greek Seas, within the 200 m depth contour. It may be found far from the coasts in the Aegean plateau, since the depth may still be suitably low. It has also been observed a few times above the continental slope. The average depth and distance from the coast of 303 common bottlenose dolphin sightings is 121 m (range m; sd=233) and 3.0 km (range km; sd=4.1), respectively. No offshore observations have been made along the Hellenic Trench, with the exception of a single animal south of Crete. In several areas common bottlenose dolphins share their habitat with short-beaked common dolphins. Abundance The common bottlenose dolphin is the cetacean species that is most commonly found in Greek coastal waters and the second most abundant species after the striped dolphins. There is no abundance estimate for common bottlenose dolphins in the Greek Seas. The absolute abundance of a local population unit of this species inhabiting the Amvrakikos Gulf is 148 (Bearzi et al. 2008a). Population trend Population trends are unknown, but they are not expected to differ from the suspected Mediterranean population trend, which is negative (Bearzi et al. 2008c). 40

43 Degree of residency and/or isolation According to stranding and sighting data the common bottlenose dolphin is present yearround in the Greek Seas. Mediterranean common bottlenose dolphins are genetically differentiated from those inhabiting the contiguous eastern North Atlantic Ocean (Natoli et al. 2005). Based on nuclear and mitochondrial DNA analyses, discrete populations have been identified across the Black Sea and the Mediterranean Sea. Population structure was detected and the following populations were identified: Black Sea, eastern Mediterranean, western Mediterranean, eastern North Atlantic. Significant genetic differentiation was observed between populations from the eastern and the western Mediterranean (Natoli et al. 2005). Seasonality of reproduction Strandings of three newborns with fetal folds, m long, and seven strandings of newborns or young calves of m indicate that most births occur from April to early September. One calf 1.2 m long was found stranded at the end of November. Feeding habits In Mediterranean coastal waters, bottlenose dolphins target primarily demersal prey. Reported prey items include demersal species such as European hake Merluccius merluccius, European conger Conger conger, red mullet Mullus barbatus, striped red mullet Mullus surmuletus, common cuttlefish Sepia officinalis, common octopus Octopus vulgaris and a variety of other bony fishes and mollusks (Bearzi et al. 2008c). However, epipelagic species including European pilchard Sardina pilchardus and round sardinella Sardinella aurita are important prey for bottlenose dolphins living in the Amvrakikos Gulf (Bearzi et al. 2008a), whilst those in the inner Ionian Sea predominantly target demersal prey (Bearzi et al. 2005). Main threats The two most important threats for this species in Greece and the Mediterranean in general are: 1) the reduced availability of prey caused by overfishing, and 2) incidental mortality in fishing gear (Bearzi et al. 2008c). Intentional killing is still a cause of mortality in Greece, and therefore, a threat for the species, although it seems to occur less often than in the past decades. Another developing potential or real threat is the noise produced by Acoustic Harassment Devices or Acoustic Deterrent Devices (often called pingers ; see Bearzi et al. 2008c). Massively sold to coastal artisanal fishermen and sea farm owners in order to mitigate the damage to their fishing gears or cages, they may have exclusion effects on the dolphins, which feed in the same coastal habitat that is harvested by humans. IUCN Red List classification Mediterranean subpopulation proposed as Vulnerable (Bearzi & Fortuna 2006); listed as Vulnerable globally (IUCN 2008). 41

44 42

45 Stenella coeruleoalba (Meyen, 1833) Striped dolphin Scientific name: Stenella coeruleoalba Common name: Ζωνοδέλφινο Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Zonodélfino zonoðélfino Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Stenella Species: Stenella coeruleoalba Relevant common names EN striped dolphin AR (delfin azraq wa abyad) FR dauphin bleu et blanc TR çizgili yunus ES delfín listado AL? IT stenella striata HR prugasti dupin DE Blauweißer delfin HE (stenella mefuspeset) PT golfinho riscado ML denfil geddumu qasir Size The body length of Mediterranean striped dolphins is generally shorter than in oceanic populations (reaching 2.56 m). Males are slightly larger than females (Archer II & Perrin 1999, Aguilar 2000). The average length of 110 animals stranded in Greece is 1.65 m (sd=0.39). The maximum length for males is 2.20 m and for females 2.15 m. In the Mediterranean, the longest specimen is a male 2.27 m long (Van Canneyt et al. 1998) and a female 2.25 m long (Duguy 1986). Higher reported values (2.4 to 2.8 m) should be considered dubious. Length at birth in the Mediterranean has been reported as m (Aguilar 1991). However, newborns of 0.80 m were recorded in Greece and other Mediterranean countries. Mediterranean striped dolphins are thought to have the smallest size in the world (Aguilar 2000). A 0.79 m specimen was measured by Port Police authorities following expert instructions. 43

46 Reported sightings and strandings There were 523 sightings of striped dolphins recorded all over the Greek Seas. This species is the second most common among strandings (Table 1), almost one third of all strandings (31.2% in the extrapolated data) belonging to this species. The 197 strandings recorded are spread all over Greece. Geographic range Striped dolphin records in the Greek Seas suggest that the species is present in all deep (>500 m) and pelagic waters. It is present also at intermediate depths of m. Although strandings of this species were reported from shallow or enclosed gulfs (inner Thermaikos, Pagasitikos, inner Saronikos, inner S Evvoikos) and shallow seas (Thracian Sea, inner Ionian Sea, Cyclades area), striped dolphin presence there is unlikely. Striped dolphins have been observed rarely in coastal areas. Only two sightings of striped dolphins occurred above the shallow waters of the continental shelf in the area between Lefkada, Kefallonia and Zakynthos Islands and the mainland (inner Ionian Sea), which has been surveyed intensively during the last fifteen years. The only enclosed gulf where striped dolphins regularly occur and seem to be resident or even isolated is the deep Gulf of Corinth, where they often form mixed groups with short-beaked common dolphins and occasionally with Risso s dolphins as well (Frantzis & Herzing 2002). Habitat The striped dolphin occupies the continental slope and pelagic habitat in the Greek Seas, and probably or potentially all waters beyond the 200 m contour. Exceptionally, it can be found over shallower waters (see Geographic range). It can also be found close to the coast wherever the continental slope is very steep and situated near the coastline, e.g. in the Gulf of Corinth and along the Hellenic Trench. The average depth and distance from the coast of 522 striped dolphin sightings is 1024 m (range m; sd=484) and 8.7 km (range km; sd=5.8), respectively. As the occurrence of striped dolphins is likely to extend further offshore, the average distance from the coast is certainly underestimated. Abundance The striped dolphin is apparently the most abundant species in the Greek Seas, as it is in the entire Mediterranean Sea (Forcada et al. 1994, Song of the Whale Research Team 2007). An estimate of about 120,000 individuals was made for the western Mediterranean excluding the Tyrrhenian Sea in 1991 and 1992 (Forcada et al. 1994). There is no abundance estimate for striped dolphins in the Greek Seas. Population trend Population trends in the Greek Seas are completely unknown. The Mediterranean population trend was very negative in the last two decades and suspected of a 30% reduction in the last 60 years, but it is currently uncertain (Aguilar 2006). 44

47 Degree of residency and/or isolation According to stranding and sighting data the striped dolphin is present year-round in the Greek Seas. Morphological (Calzada and Aguilar 1995, Archer 1997) and genetic (García- Martínez et al. 1995) studies show that the Mediterranean and eastern North Atlantic populations are isolated from each other, with little or no gene flow across the Strait of Gibraltar. Variation in body size within the Mediterranean basin is suggestive of population structure and/or restriction in gene flow among areas (Calzada and Aguilar 1995). The dispersal range is considered sufficiently limited among populations across the Mediterranean (and possibly between some inshore and offshore populations) to make differentiation possible, especially between the eastern and western Mediterranean basins (Gaspari 2004). A particular case of isolation concerns the small population of very few hundreds of striped dolphins inhabiting the inner part of the enclosed Gulf of Corinth. This population seems to be isolated and represents a possibly unique case of a closed population of striped dolphins. Because of its relatively small size and its isolation, this population unit seems extremely fragile and should be considered a designatable unit on the basis of precaution. Seasonality of reproduction Among the youngest stranded striped dolphins in Greece, four measured less than 0.90 m and stranded from mid July to late August, seven measured m and stranded from mid July to late August, and one measured 0.93 m and stranded the 10 th of September. These dates suggest a peak of births by the end of July and beginning of August and births mainly occurring in July and August. This apparent reproductive season appears to be a bit earlier than what has been reported for the western Mediterranean (Aguilar 1991, 2000). Feeding habits The diet of Mediterranean striped dolphins includes cephalopod species, fish and crustaceans, but cephalopods seem to be the usual prey with fish and crustaceans being more occasional (Würtz & Marrale 1991, Pulcini et al. 1992, Blanco et al. 1995). Some of the most common cephalopods include Todarodes sagittatus and Histioteuthis sp. Fish prey includes both small epipelagic (e.g. Engraulis encrasicolous) and bathypelagic species (e.g. Myctophids). No stomach content analyses have been performed so far in Greece. Main threats The most important presumed threats for striped dolphins in the Greek Seas include 1) chemical pollution, 2) intentional killing and 3) entrapment in driftnets. Biomagnification of xenobiotic compounds may be the most important threat. A die-off devastated the Mediterranean population in The primary cause of the die-off was a morbillivirus infection, but PCBs and other organochlorine pollutants with potential for causing immunosuppressive effects were suggested to have triggered the event and/or enhanced its 45

48 spread and lethality (Aguilar & Borrell 1994). Blubber concentrations of DDT and PCB, the two main organochlorine pollutants, show a slowly declining trend in the last two decades (Aguilar & Borrell, 2005) but levels are still high. Intentional killing is still a cause of mortality in the Greek Seas, although less than in the past decades. Although fishing gear damage and depredation predominantly involves common bottlenose dolphins, fishermen in the Greek Seas may not be able to discriminate among dolphin species killing in retaliation may involve other dolphin species including striped dolphins. Incidental mortality in pelagic gillnets (driftnets, ferrettare, thonailles etc.) are a major source of mortality all over the western Mediterranean, likely killing thousands of striped dolphins per year in several parts of the Mediterranean (e.g. Aguilar 2006). Their use in waters surrounding the Greek Seas is relatively limited, and seems to concern predominantly or exclusively boats belonging to the Italian and Turkish fishing fleets. No Greek boats seem to be using these nets. IUCN Red List classification Mediterranean subpopulation proposed as Vulnerable (Aguilar 2006); listed as Least Concern globally (IUCN 2008). 46

49 Delphinus delphis Linnaeus, 1758 Sort-beak common dolphin Scientific name: Delphinus delphis Common name: Κοινό δελφίνι Drawing by Massimo Demma Transcription: Pronunciation: Kinó delfíni cinó ðelfíni Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Delphinus Species: Delphinus delphis Relevant common names EN short-beaked common dolphin AR (delphin adi) FR dauphin commun TR tirtak ES delfín común AL delfin i zakonshem IT delfino comune HR dupin zlocesti DE Gemeiner delphin HE (dolphin muvhaq) PT golfinho vulgar ML denfil Size Mediterranean short-beaked common dolphins are smaller than some oceanic populations. Males are slightly larger than females (Murphy & Rogan 2006). The average total length of 32 stranded specimens measured in Greece is 1.80 m (sd=0.37). The maximum total length was 2.27 m for a male. Two specimens were reported to be 2.30 m long but the precision of these measurements cannot be confirmed. The minimum length recorded is 1.07 m and a neonate was reported to be <1 m, but no precise measurement is available. The longest specimens in the rest of the Mediterranean Sea were a male 2.24 m and a female 2.15 m (A. Cañadas, pers. comm.), while the minimum length recorded was 0.95 m (Centro Studi Cetacei 2001). The maximum length worldwide is 2.50 for males and 2.27 m for females, while the length at birth ranges between 0.85 and 1.15 m (Murphy & Rogan 2006). 47

50 Reported sightings and strandings There are 140 sightings of common dolphins recorded in the Greek Seas (many sightings from long-term dedicated surveys in the northern inner Ionian Sea have not been included). Most of the sightings come from Gulf of Corinth (52) and the northern part of the inner Ionian Sea (23). This species is the third most common among strandings (11.7% in the extrapolated data) after the common bottlenose and the striped dolphin (Table 1). Most of the 55 strandings have been recorded in areas where sightings are also available. Geographic range The short-beaked common dolphins are present in the inner Ionian Sea and in the deeper waters of the eastern Gulf of Corinth. They are present and potentially common locally in portions of the shallow waters (depth <200m) of the Aegean Sea. However, their range seems to be limited to the northern and central part of the Greek Seas, delimited by an imaginary line that crosses Greece from south Zakynthos Island to north of Rodos Island. This is probably due to primarily coastal habitat preference of the species in Greek waters, as south of that imaginary line depth increases rapidly close to the coast. No strandings and only two sightings have been recorded south of this line, despite an important effort along the Hellenic Trench, in the Myrtoon Sea, one survey in the entire and in the Cretan Sea (Gannier 2005, Song of the Whale Research Team 2007, Pelagos Cetacean Research Institute unpublished data). The single sighting south of Santorini dates back in 1986, when the status of short-beaked common dolphins may have been significantly different. The sighting in SW Kythira Island was made in 2000; however, it has not been repeated, despite the yearly surveys that cross the SW coast of Kythira Island. In the Ionian Sea the common dolphin is present only in the shallow waters between Lefkada, Kefallonia and Zakynthos Islands and the mainland. Until the mid 1990s, the shortbeaked common dolphin was the dominant species with a resident, coastal community of about 150 individuals inhabiting the waters east of Lefkada and surrounding the island of Kalamos (Bearzi et al. 2008b). The range of this community was probably covering most, if not all the inner Ionian Sea from N Lefkada to S Zakynthos, possibly including the outer Patraikos Gulf (Prokolpos Patron) as indicated by a sighting of a large group between Kefallonia and Patra in 1976 reported by Marchessaux (1980). However, a dramatic continuous decline was reported since 1996, with a ten-fold population reduction (Bearzi et al. 2008b). About 15 individuals mostly observed in S Lefkada during the last years still survive in the area (Bearzi et al. 2008b). Eight common dolphins were sighted exceptionally (no other sightings occurred in that area in the previous ten years) in SW Zakynthos in 2008 (Pelagos Cetacean Research Institute, unpublished data). Some had been already photoidentified around Kalamos Island (Giovanni Bearzi pers. comm). A small population unit (a few tens) inhabits the deep waters of the Gulf of Corinth (Frantzis and Herzing, 2002). These short-beaked common dolphins live permanently in mixed-species groups with the numerically dominant striped dolphins. Short-beaked common dolphins have never been observed in the western, shallower part of the Gulf of Corinth and the inner and outer Patraikos Gulf despite substantial effort in the area since the mid 1990s (Pelagos Cetacean Research Institute, unpublished data). Therefore, it seems likely that there is little if any exchange between common dolphins living in the inner east Ionian Sea and the Gulf of Corinth. In the Aegean Sea, the most important habitat in terms of number of animals present seems to be the Thracian Sea. Although no dedicated surveys have been conducted in this sea, the number of records are almost equal to those of common bottlenose dolphins, indicating 48

51 a similar abundance. Short-beaked common dolphins seem to be present in most of the shallow (<200 m) coastal waters of the Aegean, north of the S Cyclades. They are present in Saronikos Gulf, Hydra Island and neighbouring islets and Northern Sporades. They have been recorded in the northern Dodecanese, the Cyclades, all along the Greek islands neighbouring the Turkish coast, Agios Efstratios Island in the central Aegean, Chalkidiki peninsula, Thermaikos Gulf, in the closed Pagasitikos Gulf and in S Evvoikos Gulf. In the N Evvoikos Gulf a single individual was reported in a mixed group with common bottlenose dolphins in 2006 (M. Giannoulaki, pers. comm.). Habitat This species occupies two completely different habitats in the Greek Seas. All but one observation of short-beaked common dolphins recorded in the Greek Seas (Gulf of Corinth excluded) come from shallow (<200 m) and coastal waters. The single exception concerns a sighting made in almost 1300 m depth and dates back to 1986 (south of Santorini; G. Bearzi, pers. comm.). The average water depth and distance from the coasts of 74 shortbeaked common dolphin sightings (Gulf of Corinth excluded) is 86 m (range m; sd=233) and 4.3 km (range km; sd=5.5), respectively. Only five observations were recorded over depths greater than 200 m, and the largest distances from the coast were recorded over the large continental shelf of the Thracian Sea. In their entire shallow and coastal habitat the short-beaked common dolphins are sympatric with common bottlenose dolphins. In the Gulf of Corinth short-beaked common dolphins show habitat use that differs remarkably with that observed in other parts of the Greek Seas. In the inner part of this semi-closed gulf they show pelagic habitat preferences and they do not occur in shallow waters. The average water depth and distance from the coast of 53 short-beaked dolphin sightings in Gulf of Corinth is 713 m (range m; sd=187) and 5.9 km (range km; sd=2.4), respectively. Only five observations were recorded over depths shallower than 400 m. In the Gulf of Corinth short-beaked common dolphins are sympatric with the much more abundant striped dolphins and live only in mixed pods with them, without forming pure, single-species pods. A recent observation of short-beaked common dolphins was made in deep (approx 2500 m), offshore waters SE of Rodos Island in the Levantine Sea (Song of the Whale Research Team 2007; not included in the dataset of this report), suggesting that they might live in a pelagic environment in that deep sea. Abundance If we consider the Greek Seas as a whole, the short-beaked common dolphin is the second most common species in coastal waters and the third most common species after the striped dolphins and the common bottlenose dolphins. There is no abundance estimation for short-beaked common dolphins in the Greek Seas. The absolute abundance of the local population unit of this species inhabiting the northern inner Ionian Sea declined from about 150 in 1996 to about 15 individuals in 2007 (Bearzi et al. 2008b). The population unit that inhabits the deep waters of the Gulf of Corinth is composed of a few tens of individuals (Pelagos Cetacean Research Institute, unpublished data). 49

52 Population trend Once one of the commonest species in the Mediterranean Sea, the short-beaked common dolphin has experienced a generalised and major decrease in this region during the last years (Bearzi et al. 2003). Population trends for the Greek Seas are unknown. However, overfishing of this species prey the main cause of its rarefaction in the inner Ionian Sea (Bearzi et al. 2008b) is a source of concern. Overishing has caused a continuous decline of fish biomass in the Greek Seas since the mid 90s (Stergiou 2005, Stergiou et al. 2007, Machias et al. 2007). Therefore, the population trend is likely negative in many or most parts of the Greek Seas. The rate of population decrease may vary from one area to another. In any case, if this rate is similar to the one recorded for the population unit of the inner Ionian Sea during the last decade (Bearzi et al. 2008b), then the species could rapidly disappear from the Greek Seas. Degree of residency and/or isolation According to stranding and sighting data the short-beaked common dolphin is present yearround in the Greek Seas. Studies in the inner Ionian Sea support this hypothesis, since the majority of the known individuals were regularly observed for many years (Bearzi et al. 2008b). Recent genetic evidence (Natoli et al. 2008) indicates a relatively high degree of differentiation among short-beaked common dolphins in the Mediterranean and shows that dolphins of this species in the eastern part of the basin, including the inner Ionian Sea, are largely isolated from the western Mediterranean population. Only one sample was available from the Aegean Sea, so no differentiation between the Ionian and the Aegean Sea could be ascertained. However, distribution data suggest that geographic isolation between shortbeaked common dolphins inhabiting the Ionian and Aegean Seas is very likely. Seasonality of reproduction Only sparse information is available, indicating that births occur during the warm season. A young lactating calf 1.07 m long was found stranded in mid October, and a large fetus was found in the womb of a stranded female at the end of May. Finally, one dead newborn shorter than 1 m was found floating in late September, while its presumed mother was trying to keep it at surface (Politi pers comm.). Feeding habits The available information on the foraging ecology of common dolphins in the Mediterranean indicates relatively flexible feeding habits, with a preference for epipelagic and mesopelagic fish, similar to what has been observed outside the basin (Bearzi et al. 2003). The stomach contents from the western Mediterranean Sea indicate a diet based primarily on shoaling fish such as European anchovy Engraulis encrasicolus, European pilchard Sardina pilchardus, round sardinella Sardinella aurita and garpike Belone belone, but also on eurybathic cephalopod and crustacean species (Bearzi et al. 2003). In the waters of the inner Ionian Sea, shoaling fish including anchovies and sardines are the key prey (Clupeidae and Engraulidae account for 80% of the average diet according to Bearzi et al. 50

53 2008b). No information is available from the Aegean Sea and the Gulf of Corinth. However, the habitat and behaviour of the few short-beaked common dolphins that live in mixed pods with striped dolphins in the Gulf of Corinth indicate that a diet primarily based on cephalopods is likely. Main threats The threats most likely implicated in the decline of Mediterranean short-beaked common dolphins are diverse and include prey depletion, contamination by xenobiotics, direct killing, fishery bycatch and global climate change (Bearzi et al. 2003). However, the long-term study of the inner Ionian population unit suggested that the most important threat is prey depletion caused by overfishing (Bearzi et al. 2008b). Unsustainable fisheries exploitation resulting in food-web and other damage are an ongoing and possibly increasing threat for this and other cetacean species in Greek waters. Overfishing has caused a continuing decline of the fish stock biomass in the Greek Seas since the mid 90s (Stergiou 2005, Stergiou et al. 2007), including the short-beaked common dolphin s key prey (Machias et al. 2007). According to the available information, it seems that two more threats for this species in Greece are related to interactions with fisheries. A short-beaked common dolphin was found stranded with trammel nets around its head and lower jaws. Two more specimens that stranded in the N Aegean had marks probably originating from nets and a third one was found stranded with its flukes cut off by a knife. At least once, two or three short-beaked common dolphins were found stranded the same day in the Thracian Sea. This evidence indicates that bycatch and possibly direct killing occur and constitute a threat. Direct, intentional killing by some fishermen would not be a surprise, since it occurs for common bottlenose dolphins and striped dolphins and most fishermen do not discriminate among dolphin species. IUCN Red List classification Mediterranean subpopulation classified as Endangered (Bearzi 2003); listed as Least Concern globally (IUCN 2008). 51

54 52

55 Phocoena phocoena (Linnaeus, 1758) Harbour porpoise Scientific name: Phocoena phocoena Common name: Φώκαινα Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Fókaina fócena Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Phocoenidae (Φωκαινίδες) Genus: Phocoena Species: Phocoena phocoena Sub-species: Phocoena phocoena relicta Abel, 1905 Relevant common names EN harbour porpoise AR (khanzir al bahr) FR marsouin commun TR mutur ES marsopa común AL? IT focena comune HR obalna pliskaviča DE Schweinswal HE (foqena) PT boto ML denfil iswed Size The harbour porpoise is one of the smallest cetaceans in the world and in all populations females are consistently larger than males (Read 1999). The size of the Aegean (Mediterranean) harbour porpoise is thought to be the same of that of the Black Sea population, which is smaller than the Atlantic population (Rosel et al. 2003). The available information on body length is coming from 13 stranded specimens (M. Koutrakis, pers. comm., Pelagos Cetacean Research Institute, unpublished data). The total length of eight females was m with an average of 1.35 m (sd=0.19). The total length of six males was m with an average of 1.25 m (sd=0.08). A male 1.45 m long has recently stranded in the Turkish Aegean coasts (Güçlüsoy 2007). The maximum length worldwide is 2.08 m for a female, while the length at birth is about 0.70 m (Read 1999). 53

56 Reported sightings and strandings There is only one sighting of harbour porpoises recorded in the Greek Seas, but it has to be noted that no dedicated surveys have been conducted in the areas mainly inhabited by this species (Thracian Sea and Thermaikos Gulf). The available information regarding the species comes from 15 strandings (Table 1); of which 13 were recorded in the northern Aegean Sea. Geographic range Until the mid 1990s the harbour porpoise was considered absent or extinct in the Mediterranean Sea (Frantzis et al. 2001). Its presence is now definitely confirmed by 15 strandings and one sighting and it is limited to the northern part of the Aegean Sea. The harbour porpoise is absent from the rest of the Mediterranean basin and has been recorded exceptionally as a vagrant species close to the Gibraltar area (Frantzis et al. 2001). Until 2006 all records of harbour porpoises concerned exclusively the northernmost part of the Aegean Sea and particularly the Thracian Sea. Since 2006 three new strandings were reported further south, on both the west and east coasts of the Aegean Sea. In summer 2006 a harbour porpoise stranded alive in N Evvoia, at about latitude (Pelagos Cetacean Research Institute unpublished data). In October 2006 another specimen stranded in Urla (Turkish Aegean Sea) at of latitude (not represented on the distribution map; Güçlüsoy 2007). Finally, in spring 2008 a third specimen stranded in Kavouri Vouliagmenis in Saronikos Gulf at about a latitude of (Pelagos Cetacean Research Institute unpublished data). This is the southernmost position ever recorded for the subspecies Phocoena phocoena relicta, i.e. some 460 km further south of its previous known range in the northern Aegean and the Thracian Sea. There is no easy explanation of this appearance of harbour porpoises in southern and warmer seas, and it is unknown whether they indicate southern limits for the true range of this species. Recent observations in the area of the Çanakkale Straits (Güçlüsoy 2007, Tonay et al. 2009), both in its Aegean side and inside the straits, have shown that harbour porpoises found in the Aegean may have a continuous range with the harbour porpoises of the Marmara Sea. Habitat The harbour porpoises typically occupie the continental shelf waters close to the coast and seem to prefer lower water temperatures than the average temperatures of the Greek Seas (seldom found in waters warmer than 17 C; Read 1999). The single sighting in the Greek Seas clearly does not allow drawing conclusions about the habitat preferences of harbour porpoises in this area. However, the location of strandings indicates that the Thracian Sea encompasses the core area of its habitat. The Thracian Sea (as well as Thermaikos Gulf) has an extended plateau of shallow waters that present the lowest temperatures and salinities in the Greek Seas (Poulos et al. 1997). The only sighting of a group of 6-10 harbour porpoises occurred at about 100 m from shore (Frantzis et al. 2001). In the Black Sea, harbour porpoises occupy coastal waters up to 200 m deep, although they can also occur in deep offshore waters (Birkun & Frantzis 2006). 54

57 Abundance The population size of Aegean harbour porpoise is unknown, but likely small as indicated by the limited geographic range and rarity of records. Population trend The population trend of the Aegean Sea subpopulation or population is unknown. Degree of residency and/or isolation According to stranding and sighting data the harbour porpoises seem to be present yearround in the northern Aegean Sea. They have been recorded in all months of the year except April and September. Their small size for their age and genetic signature indicates that they originate from the Black Sea population (subspecies Phocoena phocoena relicta) rather than from the Atlantic, from which they have been reproductively isolated for thousands of years and have genetically and morphologically diverged (Rosel et al. 2003, Viaud-Martinnez et al. 2007). It has been suggested that movements of porpoises out of the the Marmara Sea and into the Mediterranean Sea may occur through the Dardanelles Straits (Rosel et al. 2003). Recent observations all along the Dardanelles Straits as well as at their exit into the Aegean Sea have shown a continuous range (Güçlüsoy 2007, Tonay et al. 2009). The population of P. p. relicta, to which the Aegean harbour porpoises belongs, may consist of three or more subpopulations, e.g. the Azov Sea, northwestern Black Sea, Marmara Sea and northern Aegean Sea (Birkun & Frantzis 2006). However, further work is needed to determine whether the animals found in the northern Aegean Sea represent a separate subpopulation, and which is their degree of geographical and/or genetic isolation from the Black and Marmara Seas (Frantzis et al., 2001; Rosel et al., 2003). Despite the recently confirmed continuous range, the genetic analysis of six samples from the Aegean Sea showed that one of their two haplotypes was shared with the Black Sea, while another was unique. Unexpectedly, all three samples from the Sea of Marmara (located between the Aegean Sea and Black Sea) possessed a single and unique haplotype. Seasonality of reproduction There is no available information regarding the reproductive season of the Aegean harbour porpoises. Reproduction is seasonal in all studied populations of this species (Read 1999). In the UK and the Baltic Sea births occur primarily in June and July. In the western Atlantic (Bay of Fundy and Gulf of Maine) they occur in May (Read 1999). Feeding habits The analysis of stomach contents of a few harbour porpoises sranded in Greece is still pending. Anchovy (Engraulis encrasicolus ponticus) is an important prey species for harbour porpoises of the Black Sea and Azov Sea populations during the cold season. At least 14 fish species have been recorded in stomach contents, of which four are considered 55

58 important: anchovy, sprat (Sprattus sprattus phalaericus), whiting (Merlangius merlangus euxinus) and gobies (Gobiidae) (Birkun & Frantzis 2006). Main threats There are no data other than from one specimen that was found with trammel nets around its pectoral fin (M. Koutrakis, pers. comm.). Bycatch is the most important threat globally and in the Black Sea, and it is one of the possible main threats for the Aegean population as well. Although no data exist, prey depletion resulting from overfishing may be another important threat. Finally, as Aegean harbour porpoises live at the southernmost limit of the range of the Black Sea population, and thus, at the highest temperatures they can afford (Poulos et al. 1997, Read 1999), climate change (already resulting in increasing sea surface temperatures in the Aegean Sea; V. Papathanasiou, pers. comm.) may be a serious threat for this population. Until 1983, unregulated hunting was the primary threat for the Black Sea population. At present, incidental mortality in fishing nets is the most serious threat there. Large-scale pelagic and small-scale coastal fisheries may also affect Black Sea harbour porpoises indirectly by reducing their prey populations and degrading their habitat (Birkun & Frantzis 2006). IUCN Red List classification The Black Sea subpopulation (thought to also include Aegean Sea animals) is proposed as Endangered (Birkun & Frantzis 2006); listed as Least Concern globally (IUCN 2008). 56

59 RARE CETACEAN SPECIES IN THE GREEK SEAS AND AROUND THEM Drawings by Massimo Demma / ICRAM 57

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61 Megaptera novaeangliae (Borowski, 1781) Humpback whale Scientific name: Megaptera novaeangliae Common name: Μεγάπτερη φάλαινα Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Megápteri fálaina meγápteri fálena Taxonomy Order: Suborder: Family: Subfamily: Genus: Species: Cetacea (Κητώδη) Mysticeti (Μυστακοκήτη) Balaenopteridae (Φαλαινοπτερίδες) Megapterinae (Μεγαπτερίνες) Megaptera Megaptera novaeangliae Relevant common names EN humpback whale AR (hout ahdab) FR mégaptère TR kambur balina ES yubarta AL? IT megattera HR grbavi kit DE Buckelwal HE (livyatan gadol snapir) PT jubarte ML baliena tal-íwienah kbar General information The humpback whale is an occasional visitor in the Mediterranean Sea, entering the region from the Strait of Gibraltar (Frantzis et al. 2004). The total length of mature individuals worldwide is 13.0 m for males and 13.9 m for females (maximum 14.8 and 15.5 m, respectively; an exceptional maximum of 17.4 m has been recorded in the southern hemisphere; the size at birth is m) (Clapham 2000). There are 13 published records of humpback whales in the Mediterranean Sea (Frantzis et al. 2004, Notarbartolo di Sciara 2006a). An additional animal was record in February 2009 off Slovenia (T. Genov, pers. comm.). It is surprising that only six of the 14 records originate from the western Mediterranean, which is closer to the Atlantic Ocean, while the other eight come from the eastern basin. Eight records concerned sightings (couples in two cases), one was a stranding and five concerned entanglements in fishing gear of whales that in all but one case died. Two sightings (in the inner Ionian and Myrtoon Sea, respectively) and one stranding (following entanglement in fishing gear) occurred in the Greek Seas. Twelve of 14 59

62 observations were made since All these whales were recorded thousands kilometers away from their usual feeding and breeding grounds, when they reached the Mediterranean Sea repeatedly during the last years. This seems to be a new, growing trend, rather than an old phenomenon that went unnoticed during the past (Frantzis et al. 2004). It is not known if the humpback whales that enter the Mediterranean are able to find their way back to the Atlantic Ocean, or if they stay in the Mediterranean Sea and die sooner or later. Frantzis et al. (2004) proposed as plausible explanations for the increased number of humpback whales in the Mediterranean the climate change and a spillover from an expanding North Atlantic population combined with the merely explorative nature of humpback whales. In all cases the high rate of entanglement in fishing gear poses a serious threat for all individuals of this species that enter the Mediterranean Sea. Reported sightings and strandings : Sightings : Strandings : 200 m contour : 1000 m contour IUCN Red List classification Listed as Least Concern globally (IUCN 2008). 60

63 Balaenoptera acutorostrata Lacépède, 1804 Northern minke whale Scientific name: Balaenoptera acutorostrata Common name: Βόρεια ρυγχοφάλαινα Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Vória rynchofálaina vória riŋxofálena Taxonomy Order: Suborder: Family: Subfamily: Genus: Species: Cetacea (Κητώδη) Mysticeti (Μυστακοκήτη) Balaenopteridae (Φαλαινοπτερίδες) Balaenopterinae (Φαλαινοπτερίνες) Balaenoptera Balaenoptera acutorostrata Relevant common names EN common minke whale AR (hout al mink) FR petit rorqual TR ticari balina ES rorcual aliblanco AL? IT balenottera minore HR kljunasti kit DE Zwergfinnwal HE (livyatan gutz) PT baleia nana ML baliena ta geddumha ppuntat General information The common minke whale is an occasional visitor in the Mediterranean Sea entering the region from the Strait of Gibraltar (Notarbartolo di Sciara 2006b). The average worldwide length of mature individuals is m in females and in males (Perrin & Brownell 2009). The maximum length recorded is 9.2 m, and size at birth is m (Notarbartolo di Sciara 1997). There are 26 records of common minke whales in the Mediterranean Sea. Three concern sightings and all the others are captured or entagled animals and a few strandings. Twenty of the records occurred in the western and only five in the eastern Mediterranean, with one more recorded in the Black Sea (Notarbartolo di Sciara 2006b). There is only one record of a young (4.16 m) common minke whale found floating dead close to Skiathos Island in May 2000 (Verriopoulou et al. 2001). 61

64 Reported sightings and strandings : Sightings : Strandings : 200 m contour : 1000 m contour IUCN Red List classification Listed as Least Concern globally (IUCN 2008). 62

65 Pseudorca crassidens (Owen, 1846) False killer whale Scientific name: Pseudorca crassidens Common name: Ψευδόρκα Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Psevdórka psevðórka Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Pseudorca Species: Pseudorca crassidens Relevant common names EN false killer whale AR (arqa mouzaïfa) FR fausse-orque TR yalanci katil balina ES falsa orca AL? IT pseudorca HR crni dupin DE Kleiner schwertwal HE (av-shen katlan) PT falsa orca ML psewdorka General information The false killer whale is probably an occasional visitor entering the Mediterranean Sea from the Strait of Gibraltar (Notarbartolo di Sciara 2006c). However, the number of recently documented occurrences of this species (especially in the eastern Mediterranean) indicates that the presence of a resident small population in the Mediterranean cannot be totally ruled out. The false killer whale is one of the largest members of the family Delphinidae, with adult males reaching 6m and females 5 m (Baird 2009). The maximum length recorded for the two sexes is 6.10 m and 5.06 m, respectively. Newborns range between 1.6 m and 1.9 m (Odell & McClune 1999). There are 33 records of false killer whales in the Mediterranean Sea; 16 in the western and 17 in the eastern basin. Nine of them concern sightings, 15 are strandings and nine are captured or entagled animals. Twelve records concerned large pods or couples (Notarbartolo di Sciara 2006c, Song of the Whale Research Team 2007). There are two records from the Greek Seas. In 1992 a pod of seven or more individuals was 63

66 photographed between Chios Island and Tsesme in Turkey. One year later a single individual stranded in Argolikos Gulf (Frantzis et al. 2003). One live stranding in the Aegean Sea occurred in Urla Bay, along the Turkish coast, in 1995 (noted with a white square on the map; Öztürk & Öztürk 1998). It is interesting to note that the last five records outside of Greece originate from the easternmost part of the Mediterranean and occurred yearly since 2003: four of them off Israel (Notarbartolo di Sciara 2006c) and one off the east coast of Cyprus (Song of the Whale Research Team 2007). Reported sightings and strandings : Sightings : Strandings : 200 m contour : 1000 m contour IUCN Red List classification Listed as Data Deficient globally (IUCN 2008). 64

67 Mesoplodon sp. Beaked whale Scientific name: Mesoplodon sp. Common name: Μεσοπλόδοντας Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Mesoplódontas mesoplóðondas Taxonomy Order: Cetacea (Κητώδη) Suborder: Suprafamily: Ziphioidea (Ζιφιοειδή) Family: Ziphiidae (Ζιφιίδες) Subfamily: Genus: Mesoplodon Species: Mesoplodon sp. Odontoceti (Οδοντοκήτη) Hyperoodontinae (Υπερωοδοντίνες) Relevant common names EN beaked whale AR (?) FR mésoplodon TR? ES mesoplodon AL? IT mesoplodonte HR? DE Zweizahnwal HE (mesoplodon) PT baleia de bico ML? General information The beaked whales of the genus Mesoplodon are among the least known mammals on Earth. They are elusive animals, difficult to study and to identify at the species level when encountered at sea (Mead 1989). There are 14 recognised Mesoplodon species in the world (Mead 2009). They are all smaller than the most common ziphiid, the Cuvier s beaked whale. The maximum lengths of 13 species range between 4.43 m and 5.64 m and the larger 14 th species reaches 6.15 m (Mead 1989). The genus Mesoplodon is vagrant in the Mediterranean Sea (Notarbartolo di Sciara 2006d). Two or three species have been recorded in five separate records. They concern the species M. densirostris, M. europaeus and possibly M. bidens. Four records come from the western Mediterranean (Notarbartolo di Sciara 2006d) and only one, more recent, from the north Levantine Sea (Notarbartolo di Sciara 2009). On 9 January 2009 a live, adult female specimen of the genus Mesoplodon 65

68 stranded in Fethiye, Turkey (see white square on the map) and left the coast after being rescued. The animal was about 5 m long and despite the good photos that are available, the species cannot be identified with certainty, although M. europaeus seems the most probable candidate (Notarbartolo di Sciara 2009). A dubious record of M. densirostris is available for the Ionian Sea. A group of four ziphiids was observed between the Messina Strait and Kefallonia Island (orange question mark on the map; J. Forcada in litteris). According to the available photos this could have been a mixed-species group of M. densirostris and Ziphius cavirostris, but the quality of the photos does not allow a definitive identification. Reported sightings and strandings? : Stranding? : Possible sighting : 200 m contour : 1000 m contour IUCN Red List classification All species of Mesoplodon are listed as Data Deficient globally (IUCN 2008). 66

69 Steno bredanensis (G. Cuvier in Lesson, 1828) Rough-toothed dolphin Scientific name: Steno bredanensis Common name: Στενόρυγχο δελφίνι Drawing by Massimo Demma / ICRAM Transcription: Pronunciation: Stenóryncho delfíni stenóriŋxo ðelfíni Taxonomy Order: Cetacea (Κητώδη) Suborder: Odontoceti (Οδοντοκήτη) Suprafamily: Delphinoidea ( ελφινοειδή) Family: Delphinidae ( ελφινίδες) Genus: Steno Species: Steno bredanensis Relevant common names EN rough-toothed dolphin AR (dolphin khechin el asnan) FR sténo TR kaba dişli yunus ES delfín de dientes rugosos AL? IT steno HR grubozubi dupin DE Rauzahndelfin HE (dolphin tlum-shinaim) PT caldeirão ML denfil tat-tikki General information The rough-toothed dolphin is considered an occasional visitor entering the Mediterranean Sea from the Strait of Gibraltar (Notarbartolo di Sciara 2006e). However, the number of recently documented occurrences of schools of this species in the eastern Mediterranean and particularly off Israel indicates that the existence of a small resident population in the eastern Mediterranean seems to be increasingly likely. Their maximum length worldwide is 2.65 m and 2.55 m for males and females, respectively (Jefferson 2009). There are 18 records of rough-toothed dolphins in the Mediterranean Sea (Notarbartolo di Sciara 2006e, Song of the Whale Research Team 2007, Gonzalvo 2009). It is worth noting that only four of these records originate from the western portion of the Mediterranean, closer to the Atlantic Ocean. The larger number (N=14) of records in the eastern Mediterranean and their persistence in time (from 1949 to 2009) supports the hypothesis that a small population occurs there. Five records concern sightings of groups ranging from 8 to160 individuals), six are strandings, five concern animals bycaught in fishing gear and three concern osteological 67

70 material obtained under unknown circumstances. There is only one record in proximity to the Greek Seas and it concerns a group of eight animals observed in 2003 off W Kefallonia Island (Lacey et al. 2005). Two more sightings in areas neighbouring to the Greek Seas were made off N Cyprus and off the Libyan coasts in 2007 (Song of the Whale Research Team 2007). Reported sightings and strandings : Sighting : 200 m contour : 1000 m contour IUCN Red List classification Listed as Least Concern globally (IUCN 2008). 68

71 FALSE REPORTS OF CETACEAN SPECIES IN THE GREEK SEAS Apart from the species presented in this report as recorded in the Greek Seas, some more cetacean species have appeared in scientific publications, conference proceedings, popular articles, official state booklets or other documents. After checking thoroughly the original data of each of those cases, six more species were found to have been incorrectly included in the Greek cetacean fauna in the past. These are: the Sowerby's beaked whale Mesoplodon bidens, the Blainville's beaked whale Mesoplodon densirostris, the long-finned pilot whale Globicephala melas, the white whale or beluga Delphinapterus leucas, the killer whale Orcinus orca and the blue whale Balaenoptera musculus. Below we provide details for each of those cases. The floating carcass of a beaked whale was originally reported as a Sowerby's beaked whale (Mesoplodon bidens; Poulopoulos 1989). In a later paper the same case was presented as Blainville's beaked whale (Mesoplodon densirostris; pers. comm. by G. Poulopoulos in Cebrian and Papaconstantinou 1992) and later it was identified again as Sowerby's beaked whale (Mesoplodon bidens; Frantzis et al. 2003) according to the early published descriptions from in situ observations and the available low quality photos in the original paper (Poulopoulos 1989). The recent discovery of the original photos showed that the descriptions did not correspond to reality, since this animal was clearly a Cuvier s beaked whale. Original photos from another stranded cetacean showed that this was a false killer whale despite the stranding form filled by local authorities that reported a stranded long-finned pilot whale (Androukaki and Tounta, 1994). Due to a wrong assumption the white whale (Delphinapterus leucas) was referred to as accidental species in the Greek Seas (Cebrian and Papaconstantinou, 1992). The authors thought that a specimen found wandering along the coasts of the Black Sea had previously crossed the Aegean Sea; however, later it became known that the whale had escaped from an Ukrainian delphinarium in the Black Sea. The blue whale (Balaenoptera musculus) incorrectly appeared in editions, leaflets and posters of some public services, based on a single fisherman s report referring to a 30 m long whale. McBrearty et al. (1986) mentioned a sighting of a lone killer whale (Orcinus orca) in the Aegean Sea and a sighting of long-finned pilot whales (Globicephala melas) in southern Greece. One more killer whale sighting from the Aegean Sea exists in the literature as personal communication from McBrearty (Hammond and Lockyer, 1988). We looked for McBrearty s original data, but we learned that he let colleagues know that he destroyed them some decades ago after he wrote his paper (P. Evans, pers. comm.). Anyway, these data originated from individual observers who were not specialists (i.e. fishermen, yachtsmen, captains, etc.), and species identifications were often retained even 69

72 without supporting photographic documents (McBrearty et al., 1986; P. Evans, pers. comm.). Long-finned pilot whale and killer whale sightings have been reported several times from amateurs, but whenever photos or videos were available they turned out to be misidentifications (mainly of Risso s dolphins). No records of pilot and killer whales were accompanied by supporting evidence, although the accidental occurrence of these two species in the Greek Seas cannot be ruled out. 70

73 WHAT IS KNOWN, WHAT REMAINS UNKNOWN There is solid data regarding the species composition of the Greek cetacean fauna. Eight species are present in the Greek Seas; almost all year round, with two of them (harbour porpoise, fin whale) requiring some further data to consolidate the possible seasonality of their occurrence. Three more species are occasional visitors and have rarely been recorded in the Greek Seas. Finally, rough-toothed dolphins inhabit occasionally or permanently the offshore waters of the eastern Mediterranean and have been recorded in relative proximity to the Greek Seas. Current knowledge indicates that the local populations units of four species - sperm whales, Cuvier s beaked whales, short-beaked common dolphins, harbour porpoises - in the Greek Seas are among the most important in the entire Mediterranean Sea. The last of these species does not inhabit any other part of the Mediterranean Sea than the Thracian and northern Aegean Seas. The general geographic range of most cetacean species can be inferred with a satisfactory degree of precision from the distribution maps presented in this report, in a way that general conclusions or general comparisons with future data are possible. However, gaps of knowledge still exist at the level of local seas, with the exception of the Greek Ionian Sea, the west and south Hellenic Trench and the Gulf of Corinth. Surveys in several areas of the Aegean Sea are needed to understand the extent of occurrence of several species with higher precision. Since sighting data are coming mainly from the warm season, winter surveys are also necessary to detect seasonal changes in occurrence of some species. Data regarding ecology and feeding habits, genetics and stock discreteness, life history, toxicology, histopathology, causes of death, biometry etc. are scarce and fragmentary. In addition, limited information is available on anthropogenic threats and their relative importance per species. Such data and information are crucial for species conservation and for the management of human activities that have an impact on their populations. Although their collection is relatively easy and of low cost in comparison to open sea surveys and other methods, the lack of a properly organized national stranding network leaves a large number of cetacean carcasses uninspected, resulting in loss of valuable information. The most important knowledge gap concerns the absolute abundance of each cetacean population. With the exception of one very small common dolphin population unit in the inner Ionian Sea, one isolated bottlenose dolphin population unit in Amvrakikos Gulf, and the sperm whales along the Hellenic Trench, we have not even rough estimations of absolute 71

74 abundances for any species in the entire Greek Seas. Research aimed to produce abundance estimates and trends is of high priority. Cetacean conservation demands the careful design and application of management measures for each species that will guarantee the survival of a population large and healthy enough to prosper. At present, however, there is no possibility of testing the effectiveness of any management measure, except for a very few areas, due to the unknown abundance and status of most populations. Although there has been progress in our knowledge on cetaceans inhabiting the Greek Seas during the last 15 years, we are still far from understanding the complexity of their ecology, and in most cases we remain unable to monitor their status. Given the gaps in the current knowledge regarding cetacean populations in Greece, there is still a lot of scientific work needed so that conservation efforts can start to be effective at the national level. 72

75 ARE THE GREEK CETACEAN POPULATIONS DECLINING? The data of this report and previous studies have shown that eight cetacean species inhabit the Greek Seas. Crucial data on the abundance and the population status and trend of these species at the national level are not available. However, information from portions of the Greek Seas and the rest of the Mediterranean Sea suggest that most cetacean species populations are likely to be declining, some even at alarming rates. Perhaps the most revealing example is that of the short-beaked common dolphin. Once one of the commonest species in the Mediterranean Sea, common dolphins have experienced a generalised and major decrease in this region during the last years (Bearzi et al. 2003). At least in the inner Ionian Sea, overfishing of this species prey has caused its dramatic rarefaction (Bearzi et al. 2008b). Overfishing is known to occur in many other parts of the Greek Seas, with a continuous decline of fish biomass since the mid 90s (Stergiou 2005, Stergiou et al. 2007, Machias et al. 2007). As a result, depletion of key cetacean prey can be expected. While the rate of population decrease may vary from one area to another, the alarmingly rapid decline of common dolphins in the inner Ionian Sea (Bearzi et al. 2008b) suggests that important cetacean populations can rapidly disappear from the Greek Seas. Prey depletion is one of the threats that may drive the apparently small population unit of the Aegean harbour porpoises to decline and potentially to extinction. In the north Aegean this species lives at the limit of the highest temperatures it can afford (Poulos et al. 1997, Read 1999); therefore, increasing sea surface temperatures in the Aegean Sea (V. Papathanasiou, pers. comm.) may threaten its survival. The population of sperm whales in the Greek Seas is also very small (Pelagos Cetacean Research Institute, unpublished data). Populations of a few hundreds of individuals may disappear even by natural changes in their environment. In the case of sperm whales in Greece, mortality caused by ship strikes alone seems unsustainable, and further threatens this small population (Pelagos Cetacean Research Institute, unpublished data). Ingetsion of plastic debris is yet another anthropogenic cause of mortality. The population trend for common bottlenose dolphins and striped dolphins in the Greek Seas are unlikely to differ significantly from trends in the whole Mediterranean region. Such trends are thought to be negative for bottlenose dolphins (Bearzi et al. 2008c), and was very negative in the last two decades, but currently uncertain for striped dolphins (Aguilar 2006). 73

76 A drastic decrease in sightings and strandings of Cuvier s beaked whales along the Hellenic Trench (with no reduction in search effort) during the last decade raises concern over a possible population decline. Two mass stranding events removed a relatively high number of individuals (at least 23) from local populations, but the total number of animals that died without reaching the coasts may have been much higher. The impact of the use of military sonar along the Hellenic Trench seems important at the population level (Frantzis 1998, 2004), and may have dramatic consequences. The Mediterranean population of five out of eight cetacean species that inhabit the Greek Seas are considered as Endangered (sperm whale, common dolphin, harbour porpoise), or Vulnerable (common bottlenose dolphin, striped dolphin; Reeves & Notarbartolo di Sciara 2006). As the local population units of four species in the Greek Seas (sperm whale, Cuvier s beaked whale, short-beaked common dolphin and harbour porpoise) are likely among the most important (in terms of sighting frequencies, habitat, reproduction, uniqueness etc.) in the entire Mediterranean Sea, ensuring their long-term survival is mandatory. Although no population trends are available for any cetacean species in the Greek Seas, local studies, knowledge from other Mediterranean areas, evidence of increasing threats, as well as the apparently small size or uniqueness of several cetacean populations in the Greek Seas, all call for urgent conservation measures. 74

77 ACKNOWLEDGEMENTS Many thanks to several research centres, organisations and persons that have offered stranding and sighting data, namely the Hellenic Centre for Marine Research (Greece) and particularly Dr. Papakonstantinou, Dr. Panayotidis, Dr. Mariolina Corsini-Foka and Dr. Marianna Giannoulaki, Fisheries Research Institute (Kavala) and particularly Dr. Manos Koutrakis, Pelagos Cetacean Research Institute, MOm (Hellenic Society for the Study and Protection of the Monk Seal), Tethys Research Institute, WWF Greece, Greenpeace Greece, GREC (Group de Recherche sur les Cétacés, France), IFAW (International Fund for Animal Welfare), Ocean Alliance (Mediterranean Voyage of the Odyssey), Michael White, Manolis Bardanis (Naxos Diving Centre), Sotiris Diamantis (Mystic Blue), Giannis Gavalas, Aristidis Valoukas, Stelios Gialinakis and a long list of friends, colleagues and supporters of the Pelagos Cetacean Research Institute, who contributed documented strandings or opportunistic sightings. Gratitude is expressed to the Greek Port Police authorities that have collaborated in the stranding network and to the Port Police Directorate of the Ministry of Mercantile Marine, Aegean and Island Policy that offered access to their archives. Many thanks to Voula Alexiadou for maintaining and updating the sighting and stranding database of the Pelagos Cetacean Research Institute and to Popi Gikopoulou, who estimated depths and distances from the coast. Special thanks to an anonymous donor and the Blue Planet Shipping Ltd for providing the R/V Nereis for the surveys of the Pelagos Cetacean Research Institute. Many thanks to Voula Alexiadou, Giorgos Paximadis, Popi Gikopoulou, Natalia Tsoukalas, Pantelis Kiofentzis, Makis Pagidas, Olga Nikolaou, Gilda Hassidis, Evi Tsougiopoulou and all the ecovolunteers who supported the fieldwork of the Pelagos Cetacean Research Institute during dedicated surveys or necropsies of stranded animals. Dr. Giovanni Bearzi, Dr. Giuseppe Notarbartolo di Sciara and MOm helped improve this report with many constructive comments. 75

78 LITERATURE CITED Aguilar A Calving and early mortality in the western Mediterranean striped dolphin, Stenella coeruleoalba. Can. J. Zool. 69: Aguilar A Population biology, conservation threats, and status of Mediterranean striped dolphins (Stenella coeruleoalba). J. Cetacean Res. Manage. 2(1): Aguilar A Striped dolphin Stenella coeruleoalba (Mediterranean subpopulation). Pp in Reeves R., Notarbartolo di Sciara G. (compilers and editors). The status and distribution of cetaceans in the Black Sea and Mediterranean Sea. IUCN Centre for Mediterranean Cooperation, Malaga, Spain, pp Aguilar A., Borrell A Abnormally high polychlorinated biphenyl levels in striped dolphins (Stenella coeruleoalba) affected by the Mediterranean epizootic. Sci. Total Environ. 154(2-3): Aguilar A., Borrell A DDT and PCB reduction in the western Mediterranean in , as shown by levels in dolphins. Mar. Environ. Res. 59(4): Androukaki E., Tounta E A study of the distribution and pathology of cetaceans in Greece. In European Research on Cetaceans 8 (P.G.H. Evans, ed.), European Cetacean Society, Cambridge, pp Archer II F.I., Perrin W.F Stenella coeruleoalba. Mammalian Species 603: 1-9. Azzellino A., Gaspari S., Airoldi S., Nani B Habitat use and preferences of cetaceans along the continental slope and the adjacent pelagic waters in the western Ligurian Sea. Deep-Sea Research I 55: Baird R.W False killer whale Pseudorca crassidens. In Encyclopedia of Marine Mammals, Second Edition (W.F. Perrin, B. Wursig, J.G.M. Thewissen eds), Academic Press, London, pp Bauer K Cuvier s Schnabelwal Ziphius cavirostris Cuvier 1823 im östlichen Mittelmeer. Ann. Naturhist. Mus. Wien, 81: Bearzi G., Reeves R., Notarbartolo-di-Sciara G., Politi E., Canadas A., Frantzis A., Mussi B Ecology, status and conservation of short-beaked common dolphins Delphinus delphis in the Mediterranean Sea. Mammal Rev. 33(3): Bearzi G Short-beaked common dolphin Delphinus delphis (Mediterranean subpopulation). In: IUCN IUCN Red List of Threatened Species. < Bearzi G., Politi E., Agazzi S., Bruno S., Costa M. Bonizzoni S Occurrence and present status of coastal dolphins (Delphinus delphis and Tursiops truncatus) in the eastern Ionian Sea. Mar. Freshw. Ecosyst. 15: Bearzi G., Fortuna M. C Common bottlenose dolphin Tursiops truncatus (Mediterranean subpopulation). Pp in Reeves R., Notarbartolo di Sciara G. (compilers and editors). The status and distribution of cetaceans in the Black Sea and Mediterranean Sea. IUCN Centre for Mediterranean Cooperation, Malaga, Spain, pp

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85 ANNEX I: Distribution of searching effort in the Greek Seas The following map provides an approximate figure of the effort that has been dedicated by various research teams in searching cetaceans in the Greek Seas. The information was gathered from published studies or unpublished results that have been contributed to the dataset of this report. The vast majority (more than 95%) of the results of the total effort in terms of sightings appears on the sighting and stranding distribution maps of Annex II. Sightings recorded out of the areas to which effort has been dedicated, originate from opportunistic observations. Figure 2. Distribution of searching effort of dedicated cetacean surveys conducted by various research teams in the Greek Seas. Black color represents regular and intensive effort in the framework of long-term research programs. Dark grey color represents areas that have been surveyed at least three times, irregularly in time. Light grey color represents areas that have been surveyed sporadically and less than three times. Light blue areas have not been surveyed at all. All sighting information regarding these areas (see Annex II) comes from opportunistic observations. 83

86 ANNEX II: Distribution maps of sightings and strandings Important Note: Caution is due to the interpretation of the number of sightings recorded per species as it appears in the following maps. They represent only the distribution of the presence of each species in the Greek Seas. Data include both opportunistic sightings and results of dedicated surveys that used different methods. Even more importantly, some areas have been surveyed intensively or more systematically than others (Figure 2 in Annex I) and some areas have not been surveyed at all. As a result the number of sightings recorded per species cannot be used to infer abundance or relative sighting frequencies of different species. Figure 3. Distribution of all identified cetacean stranding ( ) and sighting ( ) records in the Greek Seas. The high density of sightings in some areas is due to higher effort there, particularly in the Hellenic Trench, Gulf of Corinth, parts of the Cretan Sea and Karpathos Island, and to a lesser degree Myrtoon Sea and Northern Sporades- Chalkidiki). Please refer to Annex I in order to avoid a misinterpretation of this figure. 84

87 FIN WHALE (Πτεροφάλαινα) Balaenoptera physalus : Sightings : Strandings : 200 m contour : 1000 m 85

88 SPERM WHALE (Φυσητήρας) Physeter macrocephalus : Sightings : Strandings : 200 m contour : 1000 m 86

89 CUVIER S BEAKED WHALE (Ζιφιός) Ziphius cavirostris : Sightings : Strandings : 200 m contour : 1000 m 87

90 RISSO S DOLPHIN (Σταχτοδέλφινο) Grampus griseus : Sightings : Strandings : 200 m contour : 1000 m 88

91 COMMON BOTTLENOSE DOLPHIN (Ρινοδέλφινο) Tursiops truncatus : Sightings : Strandings : 200 m contour : 1000 m 89

92 STRIPED DOLPHIN (Ζωνοδέλφινο) Stenella coeruleoalba : Sightings : Strandings : 200 m contour : 1000 m 90

93 SHORT-BEAKED COMMON DOLPHIN (Κοινό δελφίνι) Delphinus delphis : Sightings : Strandings : 200 m contour : 1000 m 91

94 HARBOUR PORPOISE (Φώκαινα) Phocoena phocoena : Sightings : Strandings : 200 m contour : 1000 m 92