Recovery Plan for the Blue Whale ('Balaenoptera musculus')

摘要

The world's stocks of blue whales, Balaenoptera musculus, were depleted by modern whaling, and the number of blue whales in the world's oceans is now only a small fraction of what it was early in the 20th century. Since gaining complete legal protection from commercial whaling in 1966, some populations have shown signs of recovery; others have not been adequately monitored to determine their status. Blue whales are listed as endangered under the Endangered Species Act. Although the species is often found in coastal waters, blue whales are thought to occur generally more offshore than northern right (Eubalaena glacialis) and humpback (Megaptera novaeangliae) whales. Perhaps largely because of its offshore distribution, the blue whale seems less prone, although not immune, to lethal entanglements in fishing gear and lethal strikes by vessels. Moreover, its principal prey, euphausiids, are not commercially exploited on a large scale in the Northern Hemisphere. Collisions with vessels, entanglement in fishing gear, reduced zooplankton production due to habitat degradation, and disturbance from low-frequency noise are the most obvious potential indirect threats. Thus, unlike the more piscivorous baleen whales (e.g., the humpback whale, fin whale, Balaenoptera physalus, minke whale, B. acutorostrata, and Bryde's whale, B. edeni), the blue whale in the Northern Hemisphere is probably not yet competing directly with humans for prey resources. The long-term goal of this Plan is to promote the recovery of blue whale populations so that it becomes appropriate to remove them from the list of Endangered and Threatened Wildlife under the Endangered Species Act.