Announcements. Missed Exam Policy

Transcription

1 Announcements Final: Monday, June pm Baskin Auditorium (here) Study guide available on the website. Midterm 2 key: new version, please re-download Don t forget your pink scantron If you want your final and term paper back, please give us an envelope on Monday Large Stamped Self- addressed Missed Exam Policy Missed = 5pm or later on Monday Automatic zero, unless Whenever possible, notify the instructors beforehand by AND Document emergency or illness situations We will handle legitimate absences on a case-by-case basis. 1

2 Congrats Dr. Luis Hückstädt! Marine Mammal Population Trends & Conservation (Part II) 2

3 Factors Controlling Populations Human interactions Environmental fluctuation Predator control Pollution Disease regulation Problems assessing environmental variation Cyclic fluctuations (natural)? ENSO & Pacific Decadal Oscillations Short term changes? Over fishing, needs time to recover Change to carrying capacity (long term)? 3

4 California Sea Lions 1998 ENSO 1983 ENSO 4

5 Documented Sea Ice Decline in the Arctic Benthic Foragers are Particularly Sensitive to Sea Ice Loss Increased primary productivity as nutrients released from the sea ice. Changes in water mixing with less ice means that increased productivity is not reaching the benthic communities 5

6 Walruses Ice as a haulout area during pupping and reproduction and to rest while foraging. Reduced ice haulouts shift to land further from productive areas foraging trips are not as successful (travel farther or forage in suboptimal habitat) Increased mortality due to overcrowding at haulouts (more stampedes) Polar Bears Ice is hunting and denning habitat g g Reduced foraging opportunities: fewer seals, poor quality habitat, shorter foraging season Increased distance between dens/land and hunting areas Energetic costs Drowning 6

7 Consequences of Sea Ice Changes in the Arctic Sea Ice Sea Ice - + Fishes 7

8 Another Consequence of Arctic Ice Melt: Increasing Human Activities Resource extraction Law of the Sea Science National Security Commercial Shipping Commercial Fishing Tourism 8

9 Arctic Wild West 9

10 Oil and Gas U.S. EEZ High Overlap with Beluga Whale Habitat 10

11 Documented Temperature Changes in the Antarctic Rothera Station British Antarctic Survey McClintock et al 2008 Sinif et al

12 Current conditions Summer sea ice distribution 50% increase in wind speed Model predictions 12

13 Current conditions Winter sea ice distribution 50% increase in wind speed Model predictions Alternative Food Web Pathways High krill Low krill 13

14 Likely Population Trends Land breeder Fish-Squid feeder Southern elephant seal Weddell Seal Crabeater seal Obligate Ice breeder Krill Leopard feeder- Ice seal dependent Reduction in Antarctic blue whale reproductive rate with krill decline. 14

15 Factors Controlling Populations Human interactions Environmental fluctuation Predator control Pollution Disease regulation Killer whales & Steller sea lions Is predation controlling populations? 3.7 killer whales to reduce otter population Did killer whales switch from large whales to pinnipeds? 15

16 Bering Sea Whales & Pinnipeds 1) Whale populations 2) Seal populations Causes? Change in prey availability Predator control Megafaunal collapse Great Whales Harbor Seals Steller Sea Lions Sea Otters roportion of maximum P Year 16

17 5 transients could cause the observed decline Leopard Seal Predation 17

18 Pups don t stand a chance 18

19 19

20 The population would most likely have increased without leopard seal predation on the young. 20

21 Sharks and Hawaiian Monk Seals Harbor Seals, Sable Island, Canada Bowen et al. J. Zool 21

22 Shark Predation on Harbor Seals Number killed Factors Controlling Populations Human interactions Environmental fluctuation Predator control Pollution Disease regulation 22

23 Pollution in the Marine Environment Includes many different substances: chemical compounds oil derived substances marine debris sewage-related pathogens excessive nutrients 23

24 Amplification of concentrations in food chains Trophic levels: 10-fold increase predicted Biomagnification Lipophilictransferred to offspring in milk Parts per billion Impacts of chemical pollution Generally divided into 3 categories direct mortality impaired reproduction indirect mortality 24

25 Direct mortality One record of acute chemical poisoning Mercury-contaminated contaminated disinfectant resulted in several harbor seal deaths Impaired Reproduction Direct experimentation Harbor seal study: fed diets with pollutants & without Failure occurred at implantation stage Fewer pups p born 25

26 Impaired Reproduction Field observations/research: Grey & ringed seals: associated partial to complete sterility CA sea lion: premature birth Cetaceans: Impaired Reproduction Hard to study, less conclusive evidence Reduced ovarian activity (belugas) Hermaphroditism (very rare) 26

27 Indirect Mortality Direct experimentation: Decreased immune response in bottlenose dolphins Captive harbor seals: decreased immune function Indirect Mortality Immunocompetence aggravated die-offs in: Bottlenose dolphins (Gulf of Mexico, US) Striped dolphins (Mediterranean) Baikal seals & Caspian seals Ultimate cause: morbillivirus infection 27

28 Factors Controlling Populations Human interactions Environmental fluctuation Predator control Pollution Disease regulation Disease Regulation Morbillivirus Bottlenose Dolphins Mediterranean Monk Seal : : ~200 28

29 Harbor Seals 1988: ~18, : ~22,500 (including grey seals) Disease Regulation Morbillivirus Warts Cancer Bottlenose dolphins Manatees Urogenital cancer: California sea lion Indication of immunosuppression Disease Regulation Papilloma virus 29

30 Factors Controlling Populations Human interactions Environmental fluctuation Predator control Pollution Disease regulation Other factors??? Red Tide Brevetoxins Karenia brevis Neurotoxin with eye and respiratory irritation Florida Manatees & 1996: : 81 Runoff has increase frequency, duration, and intensity. microalgae 30

31 Naval sonar-related cetacean strandings Sonar activity linked (spatio-temporally) p to strandings Sonar-related mass stranding locations (multiple events): Bahamas, Canary Islands, Mediterranean, Puerto Rico, Japan Causal mechanism(s) not established Beaked whales particularly sensitive 31

32 UK cetaceans: acute/chronic gas embolism Ecotourism Seal Bay, Kangaroo Island, Australia 110,000+ visitors/year it 32

33 Ecotourism How do we know we are not impacting the animals in an attempt to educate? 33

34 Most threatened Yangtze river dolphin (extinct??) Saimaa ringed seal Med. monk seal Ungava harbor seal Vaquita Indus river dolphin Conservation N. Atl. & Pac. Right Whale Antarctic blue whale Main threats Bycatch Habitat loss Low population size Pollution Intentional killing???? Questions? 34