VICTORIA, British Columbia - The number of new gray whale calves migrating north to Alaska seems to be down again this year, although none have been found dead along the British Columbia shoreline.
Low birth rates, high mortality and strandings in recent years have been noted by researchers who monitor the seasonal migration. Gray whales pass by California, Oregon, Washington and Vancouver Island on their annual migration north from Baja, Mexico, to the Bering and Chukchi seas off western and northwest Alaska.
Last year, 300 dead whales were found along the coast, including 15 boxcar-sized corpses of starving whales in British Columbia.
The population remains healthy at about 26,000 animals, but counters have spotted 87 new calves, the lowest number in eight years, said Wayne Perryman, biologist with the National Marine Fisheries Services in La Jolla, Calif.
The total number of new calves is estimated at 255 to 265. Not all the newborns are seen by spotters, who watch only during daylight and take Sundays off.
Perryman estimates there were 279 calves last year and 428 in 1999, compared with 1,520 in 1997.
"Reproduction has been down for three consecutive years for this population," he said.
Theories about the decline include shortages of food in northern feeding grounds. The whales eat amphipods and other tiny crustaceans.
Perryman believes there's a link between the amount of ice in the feeding grounds and the calving rate. Ice has been slow to recede in the last three years, he noted.
"Give us another five or six years, then hopefully we can figure this out," he said.
Juneau Empire ©2015. All Rights Reserved.