Some large whale species, including the humpback, are now less threatened with extinction, according to the cetacean update of the 2008 IUCN Red List. Most small coastal and freshwater cetaceans, however, are moving closer to extinction.
The humpback whale (Megaptera novaeangliae) has moved from Vulnerable to Least Concern, meaning it is at low risk of extinction, although two subpopulations are Endangered. The southern right whale (Eubalaena australis) has also moved to Least Concern.
“Humpbacks and southern right whales are making a comeback in much of their range mainly because they have been protected from commercial hunting,” says Randall Reeves, Chair of the Cetacean Specialist Group of the IUCN Species Survival Commission, who led the IUCN Red List assessment. “This is a great conservation success and clearly shows what needs to be done to ensure these ocean giants survive.”
Despite the improvement in status of these two species, the assessment revealed deterioration in the status of others. Overall, nearly a quarter of cetacean species are considered threatened, and of those, more than 10% (nine species) are listed as Endangered or Critically Endangered, the highest categories of threat. In addition, two subspecies and 12 subpopulations are listed as Critically Endangered.
Whales are under threat in many areas from ship strikes, entanglement in fishing gear, habitat deterioration, declining prey and noise disturbance.
Military sonar is another threat that particularly affects deep-diving beaked whales and other cetaceans like the melon-headed whale. Mass strandings of these species have occurred more often in the last 30 years.
“Large parts of the oceans are now filled with human-generated noise, not only from military sonar but also from seismic surveys and shipping. This noise undoubtedly affects many cetaceans, in some cases leading to their death,” says Jan Schipper, Conservation International and IUCN Global Mammal Assessment Director. “It may not always kill whales and dolphins, but it affects their ability to communicate and it can drive them away, at least temporarily, from their feeding grounds.”
Climate change is also starting to affect whales. The distribution of many species is changing, with the potential for a cascade of effects such as exposure to new diseases, inter-species competition and changes in prey populations. The Antarctic great whales, for example, depend on krill for food. As water temperatures rise, krill populations may decline, leaving such whales short of food.
“To save whales for future generations, we need to work closely with the fishing industry, the military and offshore enterprises including shippers and oil developers – and we need to fight climate change,” says Julia Marton-Lefèvre, IUCN Director General.
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