Monday, February 1, 2010

Interesting Article About Net Dropouts

A new study by Matthew Baker and Daniel Schindler of the University of Washington has some interesting findings regarding gill net dropouts, and delayed mortality. The scientists attempted to quantify the frequency of non-retention (drop out) in gill nets, and estimate the mortality of fish which showed fishery related injuries.

Their found that a startling 11-29% of sockeye on the spawning grounds showed signs of gill net dropout with a significant decline in survival to spawning associated with fishery induced injuries. In all more than half the fish that reach the spawning grounds with injuries fail to reproduce. The authors conclude that fisheries managers, in not accounting for mortality of net dropouts are likely inflating escapement estimates.

While these findings are disturbing, in Alaska, sockeye populations are robust, stable and generally well managed. In the Lower 48 however gill nets are still used in many commercial fisheries with potentially disastrous impacts, well beyond the direct take of salmon and steelhead. It is critical that managers account for net dropouts and the delayed mortality associated with gill net encounters when planning fisheries.

See an abstract of the paper here:

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