Environmental News Service – 2007-10-01 23:03:49
As noted in the story below, it is not totally clear what killed three blue whales recently that have washed up in the Santa Barbara Channel of southern California. While the biologists have identified ship strikes as the likely cause of death, some believe that Navy exercises using intense sonars offshore may have disoriented or harmed the hearing of these whales enough to be rammed by ships without hearing them in advance.
It is just a theory — however, the US Navy has been quick to deny any involvement in the whales’ deaths.
(NOTE: This is the same blue whale population that we often see on whalewatching cruise off the California coast in Monterey Bay and off San Francisco during the summer and fall months.)
— Mark J. Palmer, International Marine Mammal Project
SAN FRANCISCO, California (September 25, 2007) – The Center for Biological Diversity today formally petitioned the federal government to set speed limits for ships in the Santa Barbara Channel off southern California to protect endangered blue whales.
At least three dead blue whales have been documented in southern California over the past two weeks. The Santa Barbara Museum of Natural History, which conducted analyses of the dead whales, determined that ship strikes caused all three of the deaths.
It was reported the week of September 9 that there were about 100 blue whales in the Santa Barbara Channel and that their primary food source, tiny crustaceans called krill, was prevalent in the shipping lanes.
Most large vessels plying the Santa Barbara Channel are heading to or from the ports of Los Angeles and Long Beach. Several thousand container ships transit the channel each year.
The whales were found dead September 8, September 14, and September 21.
Preliminary results of the necropsy on the third whale indicated that the whale died of a ship strike, the museum scientists said. “The cranium was essentially smashed and there was extensive damage to the skeleton, such that during the excavation process broken ribs were falling out. The bones showed discoloration and uneven breaks indicating that the whale was alive at the point of impact with a large ship. Also, there were large dark stains in the muscle and tissue indicating that the whale bled internally and death was instant. There was no evidence of sonar damage found.”
While blue whales are regularly seen in the Santa Barbara Channel, the whales generally leave the channel by the end of August. But this year, about 100 of the whales stayed to feed in the channel, which puts them in the path of vessels using some of the busiest shipping lanes in the world.
Museum scientists have a “working theory” that domoic acid, a toxin associated with certain algal blooms, may be a contributing factor to the whales’ deaths.
“Whether the blue whales are being disoriented by military sonar, toxic algae or something else entirely, what is actually killing them is speeding ships,” said Brendan Cummings, oceans program director for the Center for Biological Diversity. “The single most effective thing we can do to protect blue whales is to slow down large ships.”
The Center’s petition asks the National Marine Fisheries Service, the U.S. agency in charge of enforcing the Endangered Species Act and the Marine Mammal Protection Act, to set a speed limit of 10 nautical miles per hour in the Santa Barbara Channel for all vessels 65 feet or larger until the whales have left the channel.
The National Marine Fisheries Service has proposed similar speed limits on the east coast to protect the critically endangered North Atlantic right whale.
“We are incredibly lucky to have one of the most incredible animals that has ever existed right off our coast,” said Cummings. “But we also have the responsibility to manage our oceans to ensure that our rich waters are not a death trap for endangered species.”
The blue whale is the largest animal that ever lived on Earth. Once numbering over 300,000, the global blue whale population was reduced by commercial whaling to an estimated 10,000 individuals.
Blue whales off California are part of a population of about 1,200 animals. Scientists estimate that more than one human-caused death each year will impede the recovery of the California population.
The public is asked to notify the Marine Mammal Stranding Network of any floating whales seen in Southern California waters. Please contact the Santa Barbara Museum of Natural History at 805-682-4711 ext. 157.
Copyright Environment News Service (ENS) 2007.
Mark Palmer is the Associate Director International Marine Mammal Project Director Wildlife Alive Subproject Earth Island Institute, 300 Broadway, Suite 28 San Francisco, CA 94133
(415) 788-3666 x139 (SF Office) (530) 758-6022 (Davis Office) (415) 788-7324 (fax)
http://www.earthisland.org/immp http://www.DolphinSafe.org http://www.DolphinSafeTuna.com http://www.SaveJapanDolphins.org