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Warm, Cold Waters Both Needed For Salmon And Bear Populations

August 4, 2012

redOrbit Staff & Wire Reports – Your Universe Online

A mix of steep, colder streams and slower, warmer ones are necessary for both salmon conservation efforts and for bears and other predators that require access to the spawning fish for sustenance, researchers from the University of Washington (UW) claim in a recent research paper.

The study, which will be presented during the Ecological Society of America‘s annual meeting in Portland, Oregon on August 8, shows that managing both warmer and colder waters allow salmon who are better suited for reproduction in one type or the other to keep their options open, the university said in a recent statement.

At the same time, that allows bears, gulls, and other animals who count on the salmon in order to sustain themselves for the remainder of the year to have a steady access of food. The concept, UW doctoral student Peter Lisi and aquatic and fishery sciences professor Daniel Schindler said, is called “hydrological diversity” and it can more than triple the amount of time which a predator has access to salmon during the summer months.

“In any one stream, salmon might spawn for two to four weeks,” Lisi said. “Animals like coastal brown bears and Glaucus-winged gulls gorge themselves at one stream for a few weeks and then just move to another stream that might have water temperatures a few degrees warmer and therefore support salmon populations that spawn at a later time. It’s easy for animals to move when such streams are as little as a mile or two apart.”

“Both Glaucus-winged gulls and brown bears have very short growing seasons at high latitudes. Salmon are a key resource that allows these species to fatten up and achieve the necessary annual growth in this short period of time,” added Schindler. “A complex landscape results in streams of differing temperature so salmon populations don’t spawn at the same time. Predators and scavengers have a much longer window of accessibility. We knew that salmon are an important seasonal resource for lots of predators and consumers. However, there is little appreciation for the importance of biological diversity within salmon for these consumers.”

The study was funded by the Gordon and Betty Moore Foundation, the National Science Foundation (NSF), and the Western Alaska Landscape Conservation Cooperative through the U.S. Fish and Wildlife Service. It will be part of a session on the link between aquatic and terrestrial systems, the university said.

Less than a month ago, the website Explore.org set up new webcams, providing live HD streaming video of giant brown bears in Alaska catching salmon in Katmai National Park, according to redOrbit.com’s own Lee Rannals. All Internet users can view the bears participating in the hunt by going to the URL “explore.org/bears.”


Source: redOrbit Staff & Wire Reports - Your Universe Online



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