Update on gray whale strandings and sightings (April, 2005)
The last two weeks has seen a large number of sightings of gray whales in Puget Sound waters as well as the first two gray whale strandings of the year in Washington State.
The most recent stranding occurred near Grayland on the outer coast of Washington between Grays Harbor and Willapa Bay. On the afternoon of 26 April 2005 a gray whale was seen alive in the surf and was reported to the Northwest Marine Mammal Stranding Network. Upon initial examination by personnel with Cascadia Research that evening the animal was dead. A necropsy was conducted on 28 April at the site of the stranding by biologists and veterinarians with Cascadia Research, Washington Department of Fish and Wildlife, and the British Columbia Ministry of Agriculture and Food. Only preliminary results of the external examination are available at this time and results from tests of tissues may not be available for several weeks.
The whale was a 8.82m (29 feet) male gray whale. This is only slightly larger than the whale that stranded at Whidbey Island on 18 April and based on size both are likely yearlings (born around January 2004). Girth measurements for both animals was well below normal for animals of this size and combined with the dry-looking blubber indicated the animal was thin and probably not in good nutritional condition at the time of death. For the length and girth of these animals, their weight was likely about 3,500 to 4,000 kg (approx. 8,000 to 9,000 lbs).
The necropsy on both animals was fairly complete since both were fresh and we were able to collect many tissues for testing for contaminants, disease, and pathology. The Grayland animal did show some scarring indicative of possible entanglement in the past but these did not appear to have caused death. The Whidbey whale showed evidence of blunt-force trauma from something like a strike from a vessel. Because both animals were thin and results of other tests are not available, it is possible other factors were involved as a cause of death for both whales and these may be revealed in coming weeks from tests on tissues.
These two strandings are the first two of gray whales this year in Washington State. Every year from 1 to 28 gray whales wash up dead in Washington State. The average has been about four a year. A major mortality event occurred in 1999 and 2000 resulting in more that 20 strandings each year in Washington and 100s of other whales found dead along the range of the gray whale from Mexico to Alaska. Many of these animals were emaciated. The gray whale population had been recovering from commercial whaling and had increased to over 20,000 animals by the late 1990s. The mortality event in 1999 and 2000 reduced that population down to an estimated 17,000. Since 2000, mortality has been low. This is the first gray whale death this year.
In recent weeks, gray whales have been regularly sighted in Puget Sound waters. We estimate about 10-12 animals are currently in Puget Sound based on sighting reports and sightings by Cascadia Research. This includes 5-7 gray whales in the Whidbey Island area and another 3-5 at other locations in southern and central Puget Sound. Many of the sightings have been of animals in unusual areas for gray whales including near Shelton, Olympia, Bremerton, and Seattle. In past years, high numbers of sightings in these types of areas have been followed by higher than normal numbers of strandings. This may reflect that some animals at the end of about 4 months of fasting, may be running out of their reserves and be searching for food in areas they are not familiar with. For additional information contact John Calambokidis, Cascadia Research, 360-943-7325.