* Winter krill down 80 percent in past 20 years
* Commercial krill catch rises
By Deborah Zabarenko, Environment Correspondent
WASHINGTON, Oct 28 (Reuters) - To protect penguins on the rapidly warming Antarctic peninsula, regulators need to ensure the survival of shrimp-like krill, the base of the food chain at the bottom of the world, marine experts said on Wednesday.
Whales and seals also depend on krill for food, the experts said in a telephone news briefing.
The numbers of Chinstrap and Adelie penguins are declining steeply along the Antarctic peninsula, the part of the southern continent that stretches northward toward South America.
This is the most dramatically warming place on the planet and a location where huge miles-wide (kilometres-wide) swarms of krill historically congregated, according to Wayne Trivelpiece, a penguin expert at the U.S. National Oceanic and Atmospheric Administration.
Krill need winter ice to survive but because of rising temperatures on the peninsula and in the waters that surround it, the area is ice-free for about four months each year, Trivelpiece said. Probably as a result, he said, winter stocks of krill have declined 80 percent in the past 20 years.
Prized as a component of fish food and nutritional supplements for people, krill are commercially harvested by factory trawlers, and the annual catch of this species rose in 2008 to 150,000 tons, from about 100,000 tons in 2007, according to the Pew Environmental Group.
To protect krill and the Antarctic sea creatures that depend on them, the Pew Environmental Group urged regulators now meeting in Tasmania to require fishing vessels to spread out geographically and over time in the southern ocean.
"This would prevent the concentration of the fisher from significantly reducing the amount of krill available for key predators, including whales, penguins and seals," the group said in a statement.
The Antarctic krill fishery is regulated by the Commission of the Conservation of Antarctic Marine Living Resources, a group of 25 countries now meeting in Hobart, Tasmania.
The commission already has recognized that the current catch limits will not protect krill or its marine animal predators because the limits cover large swaths of ocean and do little to guard against concentrated krill fishing in small areas, the Pew statement said. (Editing by Bill Trott)