R.V. Cefas Endeavour Plankton Survey. Cetacean Distribution & Relative Abundance Survey. 18 February 28 February 2009

Transcription

1 R.V. Cefas Endeavour Plankton Survey Cetacean Distribution & Relative Abundance Survey 18 February 28 February 2009 Common Dolphins ( Dave Wall) Surveyor: Peter Tuffy Ship Surveys Programme Irish Whale and Dolphin Group

2 1. Introduction The waters of Ireland s Exclusive Economic Zone (EEZ) are thought to represent one of the most important cetacean (whales, dolphins and porpoise) habitats in Europe. To date 24 species of cetacean have been recorded (Appendix II), with seven of these having been confirmed as calving within the Irish EEZ, while a number of other species are possibly calving (e.g. minke whale and northern bottlenose whale) (Berrow, 2001). In recognition of their importance for cetaceans, the Irish government declared all Irish waters (within the EEZ) to be a whale and dolphin sanctuary in 1991 (Rogan and Berrow, 1995). Despite this recognition, information on the distribution and relative abundance of cetaceans within the Irish EEZ, especially in offshore waters, is very limited (Wall et al. 2006). The Irish Whale and Dolphin Group (IWDG) have been collecting data on the distribution and relative abundance of cetaceans in Irish waters (including Northern Ireland) since The IWDG casual and constant effort sightings schemes record data mainly from land-based sightings and surveys (Berrow et al. 2001). The Group has conducted cetacean surveys on board commercial ferries since 2001, on board the Irish Marine Institute offshore research vessel Celtic Explorer since 2003 and on foreign research vessels commencing in In 2003, the IWDG initiated the Irish Scheme for Cetacean Observation and Public Education (ISCOPE), which aimed to promote better awareness and knowledge of cetaceans (whales, dolphins and porpoises) in Irish waters, by encouraging public participation in cetacean recording. Under ISCOPE II, the IWDG are committed to filling in data gaps that exist in our knowledge of the seasonal distribution and abundance of cetaceans in offshore habitats. As part of this project the IWDG conducted a cetacean distribution and relative abundance survey on board the R.V. Cefas Endeavour during their Plankton Survey of IWDG Ship Surveys Project Page 1 09/08/08

3 2. Methods The survey was conducted on board the R.V. Cefas Endeavour between the 18th of February and 28 th of February The survey commenced in Belfast and covered waters from Belfast Lough to the south of the Ards Peninsula (19 th of February), Liverpool Bay (20 th- to 27 th February) and the west coast of Wales 28 th of February. The vessel alternated between trawling for Clupeid species, towing plankton nets and acoustic surveying using multibeam in the Liverpool Bay area. The final day (28 th February) was taken up steaming along the west coast of Wales to Swansea where the trip ended. A single marine mammal observer was present on board during the survey and conducted watches from the bridge, 15.25m above sea level. Observer effort focused on a 90-degree arc ahead of the ship; however sightings located up to 90 degrees to port and starboard were included and recorded as auxiliary sightings. The observer scanned the area by eye and using 12 X 50 binoculars. Bearings to sightings were measured using a digital compass and distances were estimated with the aid of distance measuring stick. Environmental data were recorded every 20 minutes onto paper data forms and later transferred to digital (MS Excel) format. Sightings onto paper data forms and later transferred to digital (MS Excel) format. Automated position data were obtained through a GPS (Garmin72) receiver unit. The survey vessel travelled at an average speed of 8 knots when steaming and an average 3 knots while fishing and was stationary while hauling and deploying fishing gear. The vessel alternated between sampling with Midwater and Otter trawls as well as multi-depth plankton nets. Multibeam surveying was also conducted. Surveying was conducted up to sea-state 6 (Beaufort scale) and in moderate to good visibility 500m. As this was a survey onboard a vessel of opportunity, the survey was conducted in passing mode and any cetaceans that may have been sighted would not have been approached. Sightings were to be identified to species level where possible, with species identifications being graded as definite, probable or possible. Should species identification not be possible, sightings were to be downgraded (e.g. unidentified dolphin / unidentified whale / unidentified beaked whale etc.) according to criteria established for the IWDG s cetacean sightings database (IWDG 2009). IWDG Ship Surveys Project Page 2 09/08/08

4 3. Results 3.1. Environmental Conditions Environmental data were collected throughout the survey. Survey conditions were variable throughout, with Beaufort sea state % of the survey time, with Beaufort %, and Beaufort % of the survey time. Visibility was very good (>20km) at 12% of stations, good (16-20km) at 59.4% of stations, moderate (11 15km) at 19.8% of stations and poor (6-10km) at 3.6% of the stations. Visibility was very poor (>1km to 1-5km) at 5.1% of stations. Fog was recorded at 13% of stations. There was no precipitation at 87% of stations. Environmental Conditions Seastate (0-9) Visibility (1-6) Category Value Sw ell (0-3) 19/02/09am 20/02/09am 21/02/09am 22/02/09am 23/02/09am 24/02/09am 25/02/09am 26/02/09am 27/02/09am 28/02/09am Date Fig. 2 Morning and afternoon sea state (Beaufort 1-10), visibility (1-4) and swell (0-3) measurements taken daily during the survey Cetacean Survey Results There were no sightings of cetaceans made during the survey. Of the 64 hours of survey time logged 58.7% was at sea state three (Beaufort scale). Swell height never reached higher than 2 metres throughout the survey. Visibility was < 10km for 8.7% of the survey. IWDG Ship Surveys Project Page 3 09/08/08

5 Fig. 3 Visual survey effort during the current survey. (Each dot denotes an environmental record station) Seabird Activity Lists were made of all seabird species seen around the survey vessel each day, although bird counts were not conducted. Seabird diversity was moderate during the survey period. 11 bird species were recorded: kittiwake (Rissa tridactyla), lesser black-backed gull (Larus marinus) greater black-backed gull (Larus fuscus), herring gull (Larus argentatus), common gull (Larus canus), cormorant (Phalacrocorax carbo), gannet (Morus bassanus), fulmar (Fulmarus glacialis) shag (Phalacocorax aristotelis) black guillemot (Cepphus gryllee) and razorbill (Alca torda). IWDG Ship Surveys Project Page 4 09/08/08

6 Species Diversity Guillemot Common G Cormorant Shag Bird Species Herring G GBB Gull LBB Gull Kittiwake Fulmar Gannet Razorbill P ercentage D ays Observed Fig. 6. Percentage of days in which 11 seabird species were recorded. Acknowledgements Thanks to CEFAS for accommodating this survey on board the R.V. Cefas Endeavour. Thanks to the captain and crew of R.V. Cefas Endeavour for their support and assistance during the survey and to Chief scientist Steve Milligan. This survey was conducted under the ISCOPE II project and co-funded by the Northern Ireland Environment Agency, the Marine Institute, the National Parks and Wildlife Service and the Heritage council. IWDG Ship Surveys Project Page 5 09/08/08

7 4. References Berrow, S.D., Whooley, P. and Ferriss, S. (2001) Irish Whale and Dolphin Group cetacean sighting schemes: development of a system to record sightings of cetaceans (whales, dolphins and porpoises) in Irish waters. Final report to the Heritage Council (Ireland), Kilkenny. IFAW (2000) Logger 2000 software. Inter-national Fund for Animal Welfare, London. IWDG (2008) IWDG Cetacean Sightings Database (Rep. Ireland & Northern Ireland). Rogan, E. and Berrow, S.D. (1995) The management of Irish waters as a whale and dolphin sanctuary. In A.S. Blix, L. Walløe and Ø. Ulltang (eds), Whales, seals, fish and man, Amsterdam. Elsevier Science. Wall D., O Brien J., Meade J. & Allen B.M. (2006) Summer distribution and relative abundance of cetaceans off the west coast of Ireland. Biology and Environment: Proceedings of the Royal Irish Academy, 106B (2), Previous IWDG Survey Reports Wall D. (2009) Cetacean Distribution and Relative Abundance Survey during the OSS Rockall Trough Oceanographic Survey Unpublished Report to the Wall D. (2009) Cetacean Distribution and Relative Abundance Survey during the LE Niamh January Patrol Unpublished Report to Irish Naval Service, Haulbowline, Cork, Ireland. Tuffy P. (2009) Cetacean Distribution and Relative Abundance Survey during AFBI Gadoid Survey Unpublished Report to the Agriculture, Food and Biosciences Institute, Belfast. Wall D. (2008) Cetacean Distribution and Relative Abundance Survey during the LE Róisín December Patrol Unpublished Report to Irish Naval Service, Haulbowline, Cork, Ireland. Murray C. (2009) Cetacean Distribution and Relative Abundance Survey during the Marine Institute Nutrient Survey Unpublished Report to the Tuffy P. (2008) Cetacean Distribution and Relative Abundance Survey during IFREMER Groundfish Survey Unpublished Report to the French Institute for the Exploitation of the Sea. IWDG Ship Surveys Project Page 6 09/08/08

8 Murray C. (2008) Cetacean Distribution and Relative Abundance Survey during CEFAS Groundfish Survey Unpublished Report to the Centre for Environment, Food and Agriculture Sciences, Suffolk, England. Tuffy P. (2008) Cetacean Distribution and Relative Abundance Survey during AFBI Groundfish Survey Unpublished Report to the Agriculture, Food and Biosciences Institute, Belfast. Wall D. (2008) Cetacean Distribution and Relative Abundance Survey during FSS Southwest Herring Acoustic Survey Unpublished Report to the Wall D. (2008) Cetacean Distribution and Relative Abundance Survey during FSS Deep Water Survey Unpublished Report to the Marine Institute, Murray C. (2008) Cetacean Distribution and Relative Abundance Survey during AFBI Nephrops Assessment Survey Unpublished Report to the Agri-Food and Biosciences Institute, Northern Ireland. Wall D. (2008) Cetacean Distribution and Relative Abundance Survey during NIOZ Cold Water Coral Fish Survey Unpublished Report to the Royal Netherlands Institute for Sea Research and the Wall D. (2008) Cetacean Distribution and Relative Abundance Survey during FSS Blue Whiting Acoustic Survey Unpublished Report to the Baer J. (2008) Cetacean Distribution and Relative Abundance Survey during CEFAS Irish Sea Plankton Survey Unpublished Report to the Centre for Environment, Fisheries & Aquaculture Science and the Wall D. (2007) Cetacean Distribution and Relative Abundance Survey during FSS Southwest Herring Acoustic Survey Unpublished Report to the Wall D. (2007) Cetacean Distribution and Relative Abundance Survey during FSS Deep Water Survey Unpublished Report to the Marine Institute, Wall D. (2007) Cetacean Distribution and Relative Abundance Survey during NIOZ Canyons Survey Unpublished Report to the Royal Netherlands Institute for Sea Research and the Marine Institute, Wall D. (2007) Cetacean Distribution and Relative Abundance Survey during Rockall Trough Oceanographic Survey Unpublished Report to the Wall D. (2007) Cetacean Distribution and Relative Abundance Survey during FSS Northwest Herring Acoustic Survey Unpublished Report to the Wall D. (2006) Cetacean Distribution and Relative Abundance Survey during FSS Southwest Herring Acoustic Survey Unpublished Report to the Wall D. (2006) Cetacean Distribution and Relative Abundance Survey during FSS Deep Water Survey Unpublished Report to the Marine Institute, Wall D. (2005) Cetacean Distribution and Relative Abundance Survey during FSS Southwest Herring IWDG Ship Surveys Project Page 1 09/08/08

9 Acoustic Survey Unpublished Report to the Acoustic Survey Unpublished Report to the Wall D. (2005) Cetacean Distribution and Relative Abundance Survey during Irish Seabed Survey: Leg 17. Unpublished Report to the Marine Institute, O Brien J. (2004) Cetacean Distribution and Relative Abundance Survey during FSS Blue Whiting Survey Unpublished Report to the Marine Institute, Wall D., O Brien J., Meade J. & Allen B.M. (2004) Summer Distribution and Relative Abundance of Cetaceans off the West Coast of Ireland. Final report to the Heritage Council, Kilkenny, Ireland. Wall D. (2004) Cetacean Distribution and Relative Abundance Survey during the Celtic Sea Herring Acoustic Survey Unpublished Report to the O Brien J. (2004) Cetacean Distribution and Relative Abundance Survey during FSS Northwest Herring IWDG Ship Surveys Project Page 2 09/08/08

10 Appendix II: List of cetacean species recorded within the Irish EEZ and adjacent waters. Atlantic White-Sided Dolphin Lagenorhynchus actus Beluga Delphinapterus leucas Blue Whale Balaenoptera musculus Bottlenose Dolphin Tursiops truncatus Common Dolphin Delphis delphis Cuvier's Beaked Whale Ziphius cavirostris False Killer Whale Pseudorca crassidens Fin Whale Balaenoptera physalus Gervais Beaked Whale Mesplodon europaeus* Harbour Porpoise Phocoena phocoena Humpback Whale Megaptera novaeangliae Killer Whale Orcinus orca Minke Whale Balaenoptera acutorostrata Northern Bottlenose Whale Hyperoodon ampullatus Northern Right Whale Eubalaena glacialis Pilot Whale (long-finned) Globicephala melas Pygmy Sperm Whale Kogia breviceps Risso's Dolphin Grampus griseus Sei Whale Balaenoptera borealis Sowerby's Beaked Whale Mesplodon bidens Sperm Whale Physeter macrocephalus Striped Dolphin Stenella coeruleoalba True's Beaked Whale Mesplodon mirus White-Beaked Dolphin Lagenorhynchus albirostris Vagrant * Recorded only from Stranding IWDG Ship Surveys Project Page 1 09/08/08