Daily Current Affairs : 16-October-2023
Grey whales, with their distinctive humpbacked appearance and unique feeding habits, are captivating marine creatures found in the North Pacific Ocean. Recent studies have delved into the population swings of eastern North Pacific grey whales, linking these fluctuations to changing prey biomass and ice cover in the Arctic. This essay explores the fascinating world of grey whales, shedding light on their physical features, dietary habits, habitat, migration patterns, and conservation status.
Physical Features and Dietary Habits:
- Grey whales are easily identifiable by their humpbacked physique and the presence of sharp bumps along their backs instead of a dorsal fin.
- They are baleen whales, utilizing specialized baleen plates in their mouths to filter small crustaceans and other food from the water.
Habitat and Geographic Distribution:
- Grey whales predominantly inhabit shallow coastal waters in the North Pacific Ocean, staying close to the shore while feeding.
- There are two distinct populations: the eastern North Pacific stock along the west coast of North America and the western North Pacific stock primarily found along the coast of eastern Asia.
Migration Journey:
- Grey whales are renowned for their extensive migrations, covering up to 12,000 miles round trip.
- Western grey whales migrate between summer feeding grounds near Sahkalin Island, Russia, and winter feeding grounds in the South China Sea.
- Eastern grey whales migrate from the Bering and Chukchi Seas in Alaska and Russia to the west coast of the United States and Mexico for breeding and calving during the winter.
Population Swings and Changing Prey Biomass:
- Recent studies have highlighted a connection between grey whale population swings and variations in prey biomass. Fluctuations in prey availability impact the overall health and reproductive success of grey whales.
- Changes in the Arctic’s ice cover, influenced by climate change, further affect the distribution and abundance of prey species crucial to grey whales.
Impact on Conservation Status:
- The conservation status of grey whales varies between populations. The western grey whale is classified as “Critically Endangered” by the IUCN due to declining numbers and severe threats.
- In contrast, the eastern grey whale is categorized as “Least Concern” because its population remains relatively stable, although ongoing monitoring is essential to ensure its conservation.
Important Points:
- Grey Whales:
- Distinctive humpbacked appearance and absence of a dorsal fin.
- Utilize baleen plates to filter small crustaceans and other food from the water.
- Habitat and Distribution:
- Inhabit shallow coastal waters of the North Pacific Ocean.
- Two distinct populations: eastern North Pacific stock (North America) and western North Pacific stock (eastern Asia).
- Migration Patterns:
- Remarkable migrations covering up to 12,000 miles round trip.
- Western grey whales migrate between Sahkalin Island, Russia, and the South China Sea.
- Eastern grey whales migrate from Bering and Chukchi Seas in Alaska and Russia to the west coast of the United States and Mexico for breeding and calving.
- Population Swings and Factors:
- Population swings linked to changing prey biomass and ice cover in the Arctic.
- Fluctuations in prey availability impact health and reproductive success.
- Climate change-induced variations in Arctic ice cover affect prey distribution and abundance.
- Conservation Status:
- Western grey whales classified as “Critically Endangered” by the IUCN due to declining numbers and severe threats.
- Eastern grey whales categorized as “Least Concern” with relatively stable populations, requiring continuous monitoring for conservation efforts.
Why In News
As per a recent study, fluctuations in the population of eastern North Pacific grey whales, including alarming mass mortality events, are intricately linked to the shifting patterns of prey biomass and ice cover in the Arctic. These findings underscore the urgent need for comprehensive conservation efforts to safeguard both the grey whale population and its delicate Arctic ecosystem.
MCQs about Grey Whales
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What distinguishes grey whales from other marine mammals?
A. They have sharp bumps along their backs instead of a dorsal fin.
B. They have a long tail fin for swift swimming.
C. They have a streamlined body with a prominent dorsal fin.
D. They have a pointed snout and large flippers.
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Where do grey whales primarily migrate for breeding and calving during the winter?
A. Mediterranean Sea.
B. South China Sea.
C. Caribbean Sea.
D. West coast of the United States and Mexico.
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What is the main factor contributing to the population swings in eastern North Pacific grey whales ?
A. Changes in ocean temperature.
B. Fluctuations in prey biomass and ice cover in the Arctic.
C. Pollution in coastal waters.
D. Loss of habitat due to human activities.
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Which population of grey whales is classified as “Critically Endangered” by the IUCN?
A. Eastern North Pacific stock.
B. Western North Pacific stock.
C. Southern Hemisphere population.
D. Western grey whale population.
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