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Oceans

How the giants of the ocean are doing

What is the status of the most iconic species of baleen whales? Is it only hunting that endangers their survival? We take a good, hard look at our oceans.

While most species of large whales are recovering from the collapse caused by commercial exploitation in the past two centuries, some populations are still struggling. A recent report, authored by experts of the Marine Mammal Commission in the U.S., reviews their status and highlights the main threats that these giants of the oceans are currently facing. The assessment is based on the criteria used by the International Union for Conservation of Nature (IUCN)’s Red List of Threatened Species.

Baleen whales are cetaceans that use baleen plates – filtering structures made of keratin, the same protein found in our hair and nails, and attached to the upper jaw – to filter large quantities of water and extract food (krill or fish). The majority of the fourteen recognized species have been targeted by intense commercial whaling in the past centuries, which has driven them close to extinction. The moratorium implemented in 1986 by the International Whaling Commission stopped most whaling operations, with the exception of aboriginal whaling and research whaling (or whaling under objection to the moratorium) by Japan, Norway, and Iceland.

 

While causing international controversy and public contempt, current levels of whaling are not the most significant threat for most species. Other forms of human-caused mortality have been identified as the main obstacles to baleen whales’ recovery. These include by-catch, which is the accidental capture and entanglement in fishing nets, and ship strikes, the collision with large ships, a problem that is becoming more pressing as commercial traffic in the world’s oceans steadily increases. Other issues are ocean pollution, the spread of diseases, habitat degradation from oil spills and climate change, which is particularly problematic for those species that are restricted to small geographical ranges, with limited ability to move to new areas as the oceans warm up. Finally, baleen whales, like other marine mammals, can be disturbed by human activities, especially those that introduce noise in the environment (for example seismic surveys for oil and gas exploration) or directly harass the animals (such as unregulated whale watching).

Southern Right Whale
Southern right whales are doing better than their northern counterparts, with the exception of the Peru-Chile population, classified as Critically Endangered with fewer than 50 individuals © Pablo Cersosimo/robertharding/Corbis

Despite the common perception that all large whales are endangered, different species and populations within each species suffer a variable level of danger. Some populations have failed to recover from whaling exploitation and others remain threatened because of their smaller ranges. International research and management efforts are required to identify key impacts and coordinate effective conservation actions.

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