Module 4: Marine Mammals
1. Polar bears
2. Seals, walrus, sea lions
3. Toothed whales (beluga, narwhal, killer
whales, etc.)
4. Baleen whales (humpback, bowhead, grey,
northern right, etc.)
Key Biological Traits
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Large space requirements
Low reproduction potential
Long life
Risk of bioaccumulation of organic
pollutants
• Sensitive to over exploitation
Management Difficulties
• Poor estimates of population size and vital
rates (reproduction, survival, dispersal)
• Inter-jurisdiction distribution
• Difficult to regulate harvest (subsistence
and commercial)
• Highly political in nature
Terms and Concepts
Cetaceans
– Mammal species such as whales, dolphins, and
porpoises
IWC
– International Whaling Commission
MMPA
– Marine Mammals Protection Act (U.S.A.)
Polar Bears
Polar Bear Overview
• Depending on seals (ringed seals and
bearded seals)
• Distributed in distinctive stocks
• Subsistence/cultural hunting
• Subject to an international agreement on
conservation
• Token sport hunt (in Canada only)
Ringed Seals
Ringed Seal Overview
• Widely distributed (5 million)
• Feed on fish (Arctic cod) and “Arctic
shrimps”
• Most important species for subsistence
hunting (Inuit)
• Most important for clothing
• Fairly resilient to harvest
Distribution of Ringed Seals
Harp Seal
Distribution of Harp Seal
Harp Seal Overview
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Commercial hunt in spring (under quota)
Increasing in population size
May affect fish populations
Source of debate
Bearded Seal
Bearded Seal: Overview
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Heterogeneous distribution
Like thin ice, or ice flow
Secondary prey for polar bears
Excellent skin for ropes and moccasins
Walrus
Walrus Distribution
Walrus Overview
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Two stocks: Atlantic and Pacific
Source of ivory (art work)
Gregarious in distribution
Mollusk eaters (some prey on seals)
Excellent skins for ropes!
Hunt in Alaska highly regulated
Beluga Whale
Beluga Whale
Beluga Whale Populations: Circumpolar
Beluga Whale Populations: Canada
Beluga Whale Overview
• Large movements (distinct stocks)
• Important for subsistence hunting (delicacy
food)
• Hunted under quotas (by local people)
• Rich in Vitamin C (scurvy)
• Major conservation issues in some regions
Narwhal
Narwhal: Overview
• Large seasonal
movements
• Hunted for food and
tusks
• Traditional hunt only
(under quota)
Narwhal Populations
Other Whales
Other Whales: Overview
• ~50 humpbacks harvested per year in
Chukchi Sea by Alaska Inuit
• Few (1-2) bowheads harvested by Eastern
Arctic Inuit
• Subsistence hunt continued to be impaired
by past overuse of stocks (commercial
whaling)
Marine Mammals - People
• Long term dependency of
northern people on marine
mammals (seal hunters)
• Recurring issues of
conservation and public
debates
Commercial Whaling
Phase I: The Basque Fishery (Spanish)
– 1300 to late 1500 A.D.
Overview
• Focused on right whales (local depletion of
coasts of Europe)
• Expanded up to Grand Banks near
Newfoundland
• By late 1600s, right whales were almost
exterminated
Phase II: The Atlantic Arctic Fishery
Overview
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Focused on bowhead whales in North Atlantic
Early 1600sLate 1800s
Involved many shore stations
Move from Svalbard, Davis Strait, Baffin Bay, to
North water
• Risky but lucrative (£3500 a ton for whale bones)
• In 1910, 10 whaling ships hunted the Arctic: 18
pilot whales, 389 belugas, 1697 walruses, 4549
seals, 242 polar bears, and no bowhead whales
Phase III: Pacific Arctic Fishery
Overview
• U.S. whalers shift attention to North Pacific
• First, Pacific northern right whales (largely
depleted by 1850)
• Next, Pacific bowhead whales in Bering Sea (150200 whaling ships, up to 2700 bowheads killed in
1852)
• First whaling ships with steam engines pushed
hunt in North Shores of Alaska (Beaufort Sea)
Overview
• Market collapsed in 1912, which lead to an
end of whaling in the Arctic (which “saved”
humpbacks)
• In SE Alaska, whaling ended in 1930s
• In 1937, first international whaling
agreement
Required Reading
“Thar She Blows: Whaling in the Yukon and
Alaska”
(handout)
Modern “Whaling”
Case Study: Steller Sea Lions
Conservation Issues
• Slow recovery of most
baleen whale stocks
(except gray whales)
• Impair acceptance of
traditional hunts by
general public
• Atlantic right whales
at great risk
• Management of
tourism
North Atlantic Right Whale