Whale comeback

Abstract

Some whales, including the humpback, are now less threatened with extinction, according to the latest report issued by the International Union for the Conservation of Nature (IUCN) last month. Marine biologists estimate that the number of humpbacks may have grown to more than 40,000 adults and about 15,000 juveniles, following the hunting ban that began in the 1960s. The IUCN has revised its classification of the whales from “vulnerable” to “of least concern” in its annual list of endangered species. The southern right whale population also appears to have begun to recover — the number of these has believed to have doubled from around 7,500 in 1997. Randall Reeves of the IUCN said: “This is a great conservation success and shows what needs to be done to ensure these ocean giants survive.” While the assessment that numbers are growing for these two species is to be welcomed, the IUCN has gloomier news for other species. Overall, nearly a quarter of cetacean species are considered threatened and nine species are listed as endangered or critically endangered, the highest level of threat. But one of the real problems facing the IUCN is a lack of data. More than half the 44 cetacean species are considered “data deficient”, meaning future research on population numbers is a priority. And the worry is that more data could show more species in trouble. The blue whale, fin whale and sei whale all remain listed as endangered until more evidence is available of any recovery. Whales continue to face threats from ship strikes, entanglement in fishing gear, habitat deterioration, declining prey numbers and noise disturbance. And many of the smaller coastal cetaceans, such as dolphins and porpoises, face particular threats, the IUCN warns. “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 IUCN warns that the vulnerable vaquita, a porpoise in the Gulf of California, is likely to be the next cetacean to become extinct. Many are killed each year in fishing gear and only an estimated 150 remain in the wild. Researchers fear that it may soon follow the fate of the Yangtze river dolphin, now considered possibly extinct.