Each year hundreds of humpback and blue whales come to California coastal waters to feed. Unlike the gray whales that migrate along the California coast, these two species feed offshore in deeper waters. Their populations were decimated by commercial whaling and many scientists feared that blue whales may have been reduced to the point where they were doomed to extinction. Blue whales were a prime target of commercial whaling because they were the largest whale (and the largest animal that has ever lived). Recent research has revealed that a surprisingly large number of both blue and humpback whales feed on krill in California waters. The concentration of blue whales off California is higher than in any other location in the world.
Publication on blue whale distribution and movements in Marine Mammal Science, April 2009
Annual report of photo-ID on humpback and blue whales off the US West Coast. Report to SWFSC, Dec. 2009
The identification of individual whales has also revealed far larger
populations than were thought to exist in these waters. We now estimate
abundances of just over 2,000 for both blue and humpback whales for coastal
waters off the US West Coast. Though this is far more than previously thought, this emphasizes
the importance of these waters to both of these species. we have also found
very low reproductive rates of humpback whales off California and are exploring
the potential causes for this troubling finding. Of critical importance
is determining whether these populations are increasing or decreasing.