Web posted
Thursday, July 19, 2001
Unknowns: Salmon questions scientists are asking
By SHANA LOSHBAUGH
Peninsula Clarion
Scientists connected with Cook Inlet salmon productivity have identified several gaps in knowledge they want to see addressed:
Food web structure -- What do juvenile fish need to survive? Tracking the food web from the bottom up would reveal how to monitor the health of the rearing system, said Jim Edmundson, a biologist with the Alaska Department of Fish and Game.
Juvenile salmon behavior -- What do they eat? Where do they winter? Fish and Game biologist Tim McKinley said the young fish may need parts of the watershed that are still vulnerable to human-caused degradation.
Role of lake turbidity -- What are changing amounts of glacial silt doing to salmon habitat? Monitoring lake conditions may be vital to forecasting red runs. People should at least understand factors even if they cannot control them, said Mark Willette, the upper Cook Inlet research project leader at Fish and Game.
Ocean life -- Where do smolt go when they head to sea, and what happens to them there? Someday, radio transmitters may be small and strong enough to travel inside salmon smolts to sea and report their location.
Role of groundwater -- Is groundwater a big part of the Kenai? Is it clean? Does it help salmon eggs hatch? Urbanization may cut off drainage or add pollutants such as sewage or automotive oils. The Kenai Watershed Forum and the federal Environmental Protection Agency began a Kenai area groundwater study this summer to address those questions.
Role of dead salmon -- How many dead adult salmon need to be in a river or lake to sustain fish productivity for future generations?
Studies so far show that spawning salmon move protein from the sea inland. Predators such as bears move nutrients into the food chain, and biologists have traced salmon molecules into plants growing near Kenai Peninsula streams. Another study, near Seldovia, found that dead salmon rinsed out to sea fertilize seaweed, which feeds copepods, which become food for salmon smolts.
Edmundson said such research is a start, but does not explain how the nutrients travel or if current escapements are adequate. A new study is in the planning stage.
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