Threatened species of Balaenoptera musculus

Potential local threats affecting blue whales include collisions with vessels in regions of intense maritime traffic, negative interactions with aquaculture and fisheries activities, direct and indirect effects from poorly regulated whale-watching operations, and general disturbance from noise and acoustic pollution. As such, identifying priority areas for focusing conservation actions is of utmost relevance considering populations numbering the low hundreds.

Because widely migratory species, such as the blue whale, do not recognize political boundaries, it is of great importance to identify the location of corridors and critical areas where they perform their vital activities (i.e., feed, migrate, breed, calve) to provide baseline information for their conservation. Efforts must be implemented at the local, national and international scales if success is to be reached, as blue whale population recovery might be jeopardized by the loss of even a few individuals a year after being severely depleted by the whaling industry during the 20th Century.

It is estimated that under 5,000 blue whales remain from an initial population of at least 750,000. In the North Atlantic there are an estimated 1000 to 2000. In the North Pacific 1,400 to 4000 and in the Southern hemisphere about 460 to 1000 left from an estimated 250,000.