Blue whales off California. Why aren't they recovering?

Research shows Blue whales endangered by shipping
October 2011. Scientists in California have been puzzling as to why, when most large whale species have recovered well in the last 20 years, Blue whales have not.

Blue whales migrate past the Post of Los Angeles, one of the busiest in the world, between May and December. There are regular reports of ships striking the Blue whales, and at least 4 were killed in 2007. The true number may be much higher because most blue whale deaths go undocumented with the carcass sinking or the blue whale floating offshore undiscovered. Blue whales face serious risks from ship strikes especially when they use areas like LA/Long Beach on the route of the high level of shipping traffic serving these ports.

Blue whale research on occurrence off S California, abundance, and presence near shipping lanes has benefited by the recent collaborative effort between Cascadia Research and the Aquarium of the Pacific with the help of Harbor Breeze Cruises. This work has revealed a higher level of recent use of the waters off LA by Blue whales than had been known previously.

The lack of increase in blue whale populations is in contrast to many other large whale species that occur off California like Humpback, Fin, and Gray whales which have shown strong recoveries from whaling over the last 20 years.

Read on ...