L16 - Marine Mammal Trends and Conservation

Question 1

complex interactions (4)

Answer 1

1. animals
2. people
3. economy
4. laws/government

Question 2

factors controlling populations (5)

Answer 2

1. human interactions
2. environmental fluctuation
3. predator control
4. pollution
5. disease regulation

Question 3

fisheries interactions (2)

Answer 3

1. indirect - affected by loss of food or habitat

2. direct - animal caught or killed as a result of fishing

Question 4

stellar’s sea lion debate:

hypotheses for decline (3)

Answer 4

1. fishery resources are depleted
2. fish resources changed - “junk food” hypothesis
3. increased predation

Question 5

australian sea lions

Answer 5

live in area of low productivity but high fishing

Question 6

the other side (3)

Answer 6

1. marine mammals impact fisheries
2. take fish from nets, damage nets/gear
3. large populations may be limiting fisheries

Question 7

marine mammal takes:

as pest management (2)

Answer 7

1. CA sea lion vs. salmon fishery

2. overcrowding

Question 8

marine mammal takes:

harvested for products (3)

Answer 8

1. pelt and fur trade
2. food products
3. cultural practices (e.g. art, aphrodisiacs)

Question 9

problems assessing environmental variation (3)

Answer 9

1. cyclic fluctuations (natural?) - ENSO and pacific decadal oscillations
2. short term changes? - overfishing, needs time to recover
3. change to carrying capacity (long term?)

Question 10

increasing human activities (7)

Answer 10

1. oil and gas
2. law of the sea
3. science
4. national security
5. commercial shipping
6. commercial fishing
7. tourism

Question 11

killer whales and stellar sea lions (2)

Answer 11

1. is predation controlling populations?
   - 3.7 killer whales to reduce otter population
2. did killer whales switch from large whales to pinnipeds?

Question 12

bering sea whales and pinnipeds:

causes (2)

Answer 12

1. change in prey availability

2. predator control

Question 13

pollution in the marine environment (5)

Answer 13

1. chemical compounds
2. oil derived substances
3. marine debris
4. sewage-related pathogens
5. excessive nutrients

Question 14

biomagnification (3)

Answer 14

1. amplification of concentrations in food chains
2. tropic levels: 10-fold increase predicted
3. lipophilic - transferred to offspring in milk

Question 15

impacts of chemical pollution (3)

Answer 15

1. direct mortality
2. impaired reproduction
3. indirect mortality

Question 16

direct mortality (2)

Answer 16

1. one record of acute chemical poisoning

2. mercury-contaminated disinfectant resulted in several harbor seal deaths

Question 17

impaired reproduction:
direct experimentation (3)

Answer 17

1. harbor seal study: fed diets with pollutants and without
2. failure occurred at implantation stage
3. fewer pups born

Question 18

impaired reproduction:

field observations/research (2)

Answer 18

1. grey and ringed seals: associated partial to complete sterility
2. CA sea lion: premature birth

Question 19

impaired reproduction:

cetaceans (3)

Answer 19

1. hard to study
2. reduced ovarian activity (belugas)
3. hermaphroditism (very rare)

Question 20

indirect mortality:
direct experimentation (2)

Answer 20

1. decreased immune response in bottlenose dolphins

2. captive harbor seals: decreased immune function

Question 21

indirect mortality:

immunocompetence aggravates die-offs in: (4)

Answer 21

1. bottlenose dolphins (gulf of mexico, US)
2. striped dolphins (mediterranean)
3. baikal seals and caspian seals
4. ultimate cause-morbillovirus infection

Question 22

naval sonar-related cetacean strandings (3)

Answer 22

1. sonar activity linked (spatio-temporarily) to strandings
2. sonar-related mass stranding locations (multiple events):
   - bahamas, canary islands, mediterranean, puerto rico, japan
3. causal mechanisms not established