Why the humpback whale should be considered an endangered species
by | VIEW 169
Like other large cetaceans, humpback whales have also been the subject of intense hunting, which has pushed them almost to extinction; by the 1960s their population had dwindled to about 5,000 individuals, compared with an estimated 135,000 before whaling began.
Nowadays, even if the total population has once again risen to 60,000 head according to data reported in the IUCN Red List, entanglements in fishing nets, collisions with ships and noise pollution continue to be serious threats.
Humpback whales are found in waters all over the world, with the exception of some areas near the equator, in the high Arctic and in some enclosed seas. The northernmost point where they have been reported is at 81° north along the northern coast of Franz Josef Land.
They are generally coastal creatures and tend to congregate in waters above the continental shelf. Their winter breeding grounds are found around the equator, while their summer feeding grounds are located in colder waters, even near the polar caps.
Humpback whales make large-scale migrations between feeding and spawning grounds, often crossing the open ocean. Some specimens have traveled as much as 8,000 kilometers in one direction. An isolated and sedentary population feeds and reproduces in the northern Indian Ocean, mainly in the Arabian Sea around Oman.
This population has also been reported in the Gulf of Aden, the Persian Gulf and off the coasts of Pakistan and India. Currently, the IUCN Red List evaluates the humpback whale as a species at least risk with a total population of about 135,000 specimens, of which about 84,000 are adults, and a growing population trend.
Until 2008, the IUCN considered the species vulnerable. Regional estimates indicate a population of about 13,000 in the North Atlantic, 21,000 in the North Pacific, and 80,000 in the Southern Hemisphere. Of the isolated Arabian Sea population, however, only about 80 remain, and it is therefore considered endangered.
In most areas humpback whales have increased in numbers again, especially in the North Pacific. This recovery has prompted the United States, Canada and Australia to remove the humpback whale from the list of threatened species.
In Costa Rica, specifically to guarantee protection to the species, the Ballena Marine National Park was established. Nonetheless, humpback whales still face various other man-made threats, including entanglement in fishing nets, collisions with vessels, disturbance from vessel traffic and associated noise, destruction of coastal habitats and climate change.