Gray whales may have hit peak status
Record deaths suggest the Pacific cannot sustain any more


Kim Murphy (Los Angeles Times)


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This article is interesting in that it attempts to relate the coincept of carrying capacity to a whale species. Follow this link Link to FishNet issue on dogfish carrying capacityfor another consideration of carrying capacity - this time in relation to dogfish off the Northeast coast of the U.S. 

The Philadelphia Inquirer, June 27, 1999

SEATTLE - A record number of gray whales have washed up dead on West Coast beaches this year, and the number of calves migrating this season is the lowest recorded, leading scientists to speculate that the once-endangered mammals may have rebounded past the Pacific Ocean's capacity to nurture them.

If the gray whale population is indeed nearing carrying capacity along the Pacific Coast, it would mark the first time a whale species nearly wiped out by a century of hunting had recovered to its maximum potential - the largest number that the ocean can support.

Scientists cautioned that unusual ocean temperatures, a late breeding migration and food supply problems in the Arctic feeding grounds also could be affecting the whale population. But they said the 26,000 whales now plying the Pacific Coast approach what is believed to have been the population before the advent of commercial whaling in the 19th century.

"What we're seeing is not inconsistent with the idea that gray whales may be nearing what the environment can handle," said Wayne Perryman of the National Marine Fisheries Service, which has counted calves off the California coast since 1994. "What naturally limits populations generally is either space or food, and I'd guess that's what we're starting to see now."

At least 17 whales have washed up on Washington beaches, well above the average over the last 20 years. Higher-than-normal death rates have been recorded along the coasts of Oregon, California and Mexico as well.

Whale deaths in California over the last two years have been double the average in the last 15 years, reaching 15 so far, said Joe Cordero of the National Marine Fisheries Service in Long Beach, Calif. Because most whale deaths occur in June, at the end of the whales' 4,000-mile migration between Baja California and Alaska, that number is expected to rise.

As many as 65 whales have died off the coast of Mexico this year, biologists said.

Most of the dead whales this year were extremely thin, leading researchers to believe that they starved or succumbed to other problems because of their poor condition. Though most of them were juveniles - the group that typically washes ashore when there are deaths during the migration - biologists for the first time this year documented a number of nearly full-grown, 40-foot-long whales, said Joe Scordino, a biologist with the federal fisheries service in Seattle.

No one is ready to say definitely what has caused the higher number of deaths, especially as there is only a year of data. It may be that there are more deaths because there are more whales, Scordino said.

Gray whales, once they reach whatever the Pacific's carrying capacity is, could be expected to die off and to slow their reproductive rates because normal food supplies can sustain only a certain number. 

The maximum-capacity theory may fuel arguments in favor of letting the Makah Indian nation resume whaling. The tribe, in northwest Washington, has won permission to hunt five gray whales a year over the next five years. The tribe recently landed its first whale to vigorous protests. 

© 1998 Philadelphia Newspapers Inc. 


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