Study: Dead salmon carcasses vital to building healthy rivers

Posted: Monday, July 24, 2000

JUNEAU (AP) -- A new study says the carcasses of dead salmon appear to hold the key toward producing healthy young fish stocks.

The number of decaying carcasses needed to create the ideal, nutrient-rich stream may be greater than what state biologists are allowing to escape from commercial fisheries to spawn, the study said.

Mark Wipfli, who headed the research project for the U.S. Forest Service's Pacific Northwest Research Station in Juneau, said the study contains major implications for salmon management around Alaska and the Pacific Northwest.

It poses some new questions for managers who generally allocate as many salmon to commercial and other fisheries as possible while allowing just enough salmon to escape and return to freshwater streams to reproduce, he said.

Wipfli's work on natural and man-made streams is the latest in a growing body of research documenting just how critical salmon carcasses are to the ecological health of freshwater streams, plants and animals along with future generations of salmon.

Similar work by scientists in Washington state and Oregon prompted agencies to try rehabilitating ailing streams by having people toss hundreds of salmon carcasses into the waters.

Salmon carcass research here has biologists interested in using the information to revive some Alaska lakes, rivers and streams that have suffered low salmon runs.

The study even caught the eye of state Fish and Game officials who are tackling the salmon disaster on the Yukon and Kuskokwim river drainages and around Norton Sound.

''The work they're doing is very, very important,'' said Tom Kron, Fish and Game's supervisor for the impacted region.

Although Kron doesn't believe low nutrient levels are to blame for the disastrous salmon returns in Western Alaska, low runs over the past few years mean fewer decaying carcasses to nutritionally enhance the waters, which suggests trouble later.

''That's an issue for us coming off these poor years,'' he told the Anchorage Daily News. ''It's definitely a concern for the future.''

Logging, trapping, overfishing and hydropower have contributed to a decline in the health of many waterways, especially in the Pacific Northwest, where salmon runs are suffering, Wipfli said.

''People have ignored the benefits of the nutrients, but they play a role,'' he said. ''As soon as you start to break that cycle, there's a decline in nutrients, it becomes a declining spiral.

''Having those nutrients back in the stream is necessary before we can restore salmon.''

Dale Kelley, Juneau-based executive director of the Alaska Trollers Association, said the research sounds interesting and managers always can use more information, ''but I have a hard time believing that we're not reaching adequate escapements.

''Our stocks have been so healthy,'' she said. ''Our fisheries are known worldwide for being in good shape.''

Jan Konigsberg, director of Trout Unlimited's Alaska Salmonid Biodiversity Program in Anchorage, questions fisheries managers' claims of success in Alaska.

''They may say to a reporter that they've been managing well, but they know they've been lucky,'' he said. ''To other scientists, they say, 'We're just waiting for stuff to crash.' ''

Fisheries management has not placed the highest priority on what the ecosystem as a whole needs, he said.

''Its priority is to harvest the optimum number of fish and allow enough escapement for what they need to sustain,'' Konigsberg said. ''But salmon need salmon. That's the basic tenet of this research.

''The biological conservation of salmon ought to be the guiding principle.''

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