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.
The real situation could be much worse as more than half of the cetacean species (44 species) are classed as Data Deficient, meaning future research needs to be a priority. With better information, more species could well prove to be in danger. The blue whale (Balaenoptera musculus), fin whale (Balaenoptera physalus) and sei whale (Balaenoptera borealis) all remain listed as Endangered, pending more evidence of recovery.
Whales are under threat in many areas from ship strikes, entanglement in fishing gear, habitat deterioration, declining prey and noise disturbance.
Small coastal cetaceans, such as the Irrawaddy dolphin (Orcaella brevirostris), the finless porpoise (Neophocaena phocaenoides) and the South American franciscana (Pontoporia blainvillei), are now all listed as Vulnerable, meaning they are threatened with extinction.
“Too many of these small coastal cetaceans end up as bycatch in fisheries. This remains the main threat to them and it is only going to get worse,” says Reeves.
The vaquita (Phocoena sinus), a porpoise in the Gulf of California, Mexico, will most likely be the next cetacean species to go extinct. Already listed as Critically Endangered, an estimated 15% of its dwindling population is killed in gillnets every year, leaving only about 150 alive in the wild. The Yangtze River dolphin or baiji (Lipotes vexillifer) was classified as Critically Endangered, Possibly Extinct on last year’s IUCN Red List and it is feared that the vaquita will follow the same path.
“River dolphins are one of the most threatened cetacean categories, mainly because they are locked in competition with humans for dwindling freshwater resources,” says Jean-Christophe Vié, Deputy Head of IUCN’s Species Programme.
With less whale hunting over the last few decades, accidental killing in fishing gear has become the main threat to cetaceans. Besides the vaquita, the Black Sea harbour porpoise (Phocoena phocoena relicta), which moved from Vulnerable to Endangered, the North Atlantic right whale (Eubalaena glacialis) and the western gray whale (Eschrichtius robustus), already listed as Endangered and Critically Endangered respectively, are among the cetaceans most at risk from this threat.
“Disentanglement programmes to release whales captured in fishing gear, already carried out in the United States, New Zealand and Australia, help some individuals survive,” says Bill Perrin, Chair of the IUCN Cetacean Red List Authority. “However, areas of critical habitat need to be closed to certain types of fishing, at least seasonally, to ensure the survival of some species.”
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.
Notes to editors
For the 2008 IUCN Cetacean Red List the conservation status of all cetacean species has been assessed. Almost a third of cetaceans changed their Red List status, with the majority being at greater risk than previously. The assessments were carried out primarily by scientists from the Cetacean Specialist Group of the IUCN Species Survival Commission. The 2008 Cetacean Red List is a joint product of IUCN and the Global Mammal Assessment.
The IUCN Red List threat categories are the following, in descending order of threat:
• Extinct or Extinct in the Wild;
• Critically Endangered, Endangered and Vulnerable: species threatened with global extinction;
• Near Threatened: species close to the threatened thresholds or that would be threatened without ongoing specific conservation measures;
• Least Concern: species evaluated with a low risk of extinction;
• Data Deficient: no evaluation because of insufficient data.
Critically Endangered (Possibly Extinct) is not a new Red List category, but is a flag developed to identify those Critically Endangered species that are in all probability already Extinct but for which confirmation is required (for example, through more extensive surveys being carried out and failing to find any individuals).
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