The International Union for the Conservation of Nature (IUCN) just announced that the humpback whale has been upgraded to “least concern” status. This category corresponds to a low risk of extinction. The change represents an improved population size as assessed by the Cetacean Specialist Group, resulting in the downgrade from “vulnerable” status.
In fact, the current estimate puts the global humpback population at 40,000 – about 35% of the historic pre-whaling population. Humpback whales are large baleen whales that feed on krill and small fish species. They live in throughout the world’s oceans, migrating from summer feeding grounds to winter calving areas. They are large and relatively slow-swimming; their migratory routes are consistent and often follow coastlines. These factors have made them easy prey for whalers in the past.
The total population is made up of three separate groups, or stocks, including the western North Atlantic, north Pacific, and the southern oceans (south of 60 degrees south). Since 1966, humpback whales have been protected by the International Whaling Commission (IWC). Despite initial conservation measures, humpbacks were subject to an illegal hunt into the 1970s.
While the increase in humpbacks is a positive result of conservation efforts, it may also lead to problems. With rebounding numbers of whales, some whaling countries may be keen to resume the hunt. While commercial whaling is confined to Norway and Iceland – while Japan uses a scientific justification – other groups also hunt whales. Aboriginal subsistence whaling is permitted in the US, Denmark, Russia, and several Caribbean countries.
Australian researchers just identified an area where hundreds of humpback calves are sheltered. Nearly 400 pods use a particular bay – Camden Sound – off the Kimberley region of Western Australia. Breeding grounds such as this are crucial to the viability of cetacean populations. Adults teach calves to feed, swim, and interact. Conservation efforts can be focused on these known areas of congregation.
The southern right whale has also been deemed to be of “least concern” in the same IUCN announcement. However, while humpbacks and southern right whales are showing improved populations, most cetaceans are facing more sobering challenges. Out of a total of 44 cetacean species, nine are endangered or critically endangered. Several subspecies and subpopulations are also critically endangered – especially smaller coastal species. Realistically, accurate data are lacking for many species. Gathering information about migratory aquatic mammals is a challenge. But accurate data is the key to making decisions and ensuring population viability.
Threats for whales include collisions with ships, entanglement in fishing gear, changes in prey availability, and other habitat disruption. Some countries have attempted to address these problems with conservation plans. Changes to shipping lanes and disentanglement responses have helped in certain areas.
