By JANE KAY
San Francisco Chronicle
March 08, 2006
After warming ocean waters and a drop in krill numbers last spring set off a domino effect of sea life deaths, a group that advises the U.S. Department of Commerce on fishing regulations is expected today to limit the fishing of krill in federal waters, 200 miles from shore.
Regulations approved by the 19-member Pacific Fishery Management Council, which represents federal and state resource agencies, sport and commercial fishing interests and Native American tribes, are typically adopted by the Commerce Department. If approved, the rules could go into effect by September.
The few krill fisheries in the world operate in the Antarctic, British Columbia and Japan. Krill are used in fish food, but the supply doesn't meet the demand.
In 2003, California, Oregon and Washington started banning the netting of krill in state waters, which lie 3 miles out to sea. Krill fishing is already prohibited in federal waters off Alaska.
Fish-farming companies like to put dried krill in the feed of farmed salmon. Without krill in their diets, the aquaculture salmon appear grayish, a color unappetizing to consumers. When fish farms use natural additives to make salmon pink, they have to label it, sometimes discouraging potential buyers.
Scientists first considered protecting krill in May after they linked the drop in numbers to the thousands of seabirds washing up dead in northern waters. On the Farallon Islands, bird biologists reported a halt in nesting of the Cassin's and rhinoceros auklets and some cormorant and murre species. The malnourished condition of marine mammals along the coast was also correlated with the scarcity of krill.
"The krill disappeared for a few months, and we don't know where they went. That's when we realized how important krill are to the food chain," said Bill Peterson, an oceanographer with the National Oceanic and Atmospheric Administration in Newport, Ore.
In June, scientists from NOAA, Scripps Institution of Oceanography, UC Santa Cruz and other institutions met to share krill studies. The inch-long oily animals congregate where the shallow continental shelf drops down to the deep ocean. In the daytime, they live 1,000 feet deep, coming up at night to feed on phytoplankton, tiny plants.
But the scientists knew less than they had believed, such as how fast krill grow and their numbers. The scientists presented a final report to the council, which has preliminarily recommended an end to krill fishing in Pacific waters.
Scientists know that the abundance of krill is linked to the strength of winds affecting the California Current, the band of water from Baja California to British Columbia. In cold-water years, when the winds and currents come from the Northwest, there is vigorous upwelling, a phenomenon that brings up nutrients from the deep ocean to the surface.
At the surface, the nutrients feed the phytoplankton that bloom near the sunlight. Krill, or euphausiid, are large zooplankton and feed on the phytoplankton. Salmon, rockfish, squid, seabirds, seals and baleen whales, including humpbacked, blue and bowhead whales, all eat krill.
But the winds shifted in April and May, bringing El Nino-like conditions of warmer waters. Upwelling weakened and krill numbers fell, resulting in the problems for ocean life.
As the temperature of the California Current has gradually risen as a result of global atmospheric and ocean warming, scientists worry that the productivity of the current will diminish, including the abundance of krill.
"We don't know enough about the animals yet to do the calculations to discover if it's even possible to harvest them without damaging the environment," Peterson said. "The main thing is to protect the whole food chain."
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