Marine Mammal Population Trends And Conservation

Front 1

The complex interactions

Back 1

-animals
-people
-economy
-laws/government

Front 2

factors controlling animal populations

Back 2

-human interactions
-environmental fluctuations
-predator control
-pollution
-disease regulation

Front 3

human (fisheries) interaction: direct vs. indirect

Back 3

-direct: animal caught or killed as a result of fishing
-indirect: loss of food or habitat

Front 4

dangers to animals (from fisheries)

Back 4

-mortality or serious injury in trawl fishery
-intentional kills

Front 5

marine mammals impact on fisheries

Back 5

-take fish from nets
-damage nets/gear
-large populations may be limiting the amount of fish fisheries catch

Front 6

marine mammals and pest management

Back 6

-overcrowding
-california sea lion vs. salmon fishery
-in 1996 only 70 steelhead salmon made it through (normarlly 2500)

Front 7

marine mammals and harvested products

Back 7

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

Front 8

harp and hooded seal takes in canada
and northern fur seal harvest in alaska

Back 8

-270, 000 harp seal quota
-to increase cod populations
-10,000 hooded seals/year

Front 9

factors controlling populations: environmental fluctuations

Back 9

-cyclic fluctuations (natural)
-short term changes: over fishing, needs time to recover
-change to carrying capacity (long term)
-ex: arctic climate change and the effects of Increased/Decreased sea ice
*slide 49*

Front 10

examples of human activity (increases)

Back 10

-oil and gas
-law of the sea
-science
-national security
-commercial shipping
-commercial fishing
-tourism

Front 11

factors controlling populations: predator control

Back 11

-is predation controlling populations? it takes 3.7 killer whales to reduce an otter population
-did killer whales wwitch form large whales to pinnipeds?

Front 12

megafaunal collaps

Back 12

-collapse in great whales, harbor seals, steller sea lions, and sea otters
-caused by either change in prey availability and/or predator control
-ex: shark predation on harbor seals

Front 13

factors controlling populations: pollution

Back 13

-includes chemical compounds
-oil derived substances
-marine debris
-sewage-related pathogens
-excessive nutrients

Front 14

biomagnification

Back 14

-the amplification of concentrations in food chains
-trophic levels: 10-fold increase predicted
-lipophilic transferred into offspring in milk

Front 15

impacts of chemical pollution

Back 15

-direct mortality
-impaired reproduction
-indirect mortality

Front 16

direct mortality

Back 16

-one record of acute chemical poisoning
-mercury-contaminated disinfectant resulted in several harbor seal deaths

Front 17

impaired reproduction experiment

Back 17

-harbor seal study: fed diets with pollutants and without
-failure occured at implantation stage
-fewer pups born

Front 18

Impaired reproduction observation

Back 18

-grey and ringed seals: associated partial to complete sterility
-california sea lion: premature birth
-cetaceans: hard to study, less conclusive evidence
-belugas: reduced ovarian activity
-hermaphroditism (very rare)

Front 19

indirect mortality experiment

Back 19

-decreased immune response in bottlenose dolphins
-captive harbor seals: decreased immune function

Front 20

indirect mortality observation

Back 20

-immunocompetence aggravated die offs in: bottlenose dolphins, striped dolphins, baikal seals, and caspian seals
-ultimate cause: morbillivirus infection

Front 21

factors controlling populations: disease regulation

Back 21

-morbillivirus in: bottlenose dolphins, mediterranean monk seals, harbor seals and grey seals
-brevetoxins in: florida manatees

Front 22

factors controlling populations: other

Back 22

-naval sonar-related cetacean strandings: sonar activity linked to strandings
-mass stranding locations: bahamas, canary islands, mediterranean, puerto rico, japan
-uk cetaceans: acute/chronic gas embolism

Front 23

ecotourism: the question

Back 23

-how do we know we are not impacting the animals in an attempt to educate?

Front 24

conservation

Back 24

-species threatened by bycatch, habitat loss, low populaiton size, pollution, and intentional killing leads to conservation efforts