A total of five gray whales have perished in the waters surrounding the San Juan Islands over the last ten days, and all seem to have died from starvation. As we mentioned in a previous blog entry, this spate of gray whale deaths in Washington is not unusual. Large die-offs have occurred before, most recently in 1999. This might turn out to be another one of those bad years. Ominously, very few entered Magdalena Bay this winter, a critically important breeding area where we offer gray whale watching tours in Baja, Mexico.
The gray whales’ troubles this spring most likely arises from a lack of food last summer in the Bering Sea where they do almost all of their feeding. Gray whales fast most of the year and survive off of the thick blubber layer they obtain in Alaska waters each summer. Many may not have had sufficient fat reserves to have the energy needed for the rigors of breeding in the Baja lagoons. Others may not be able to survive the 1,000-1,400 mile long round-trip migration – the longest of any mammal in the world – without thick blubber to provide energy. So poor feeding conditions in the Bering Sea last year may be affecting them most strongly nearly a year later.
The gray whales that have died this year within the Salish Sea of Washington and British Columbia have had some strange stomach contents. One whale had a large quantity of sawdust in its stomach from feeding near an old sawmill. Another had a pair of sweat pants and plastic items in its stomach. These are desperately hungry whales, forced to forage in poor locations before reaching the rich feeding grounds of the Bering Sea.
So far, none of the deaths seem to be related the abundance of transient killer whales in the Salish Sea this spring. Several attacks on gray whales by transient type orcas have been witnessed recently, but none have been successful. Perhaps the orcas can sense the weakness of starving gray whales and test them to see if they can still defend themselves. The killer whales remain content with eating the abundant sea lions and harbor seals.