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Unlike other salmon species, sockeye salmon require a lake habitat during the juvenile phase of their lifecycle. Salmon Lake plays an integral part in determining the quantity of the sockeye salmon return to the Pilgrim River each year. As a result of the depleted sockeye returns in the 1990s, NSEDC helped sponsor a limnology study of Salmon Lake from 1994 to 1996. Based on this study, it was decided that fertilization of the lake would be an appropriate way to increase sockeye salmon returns.
Since 1996, NSEDC has sponsored 50% or more of the cost of lake fertilization. Fertilization leads to an increase in the growth of phytoplankton and zooplankton, which, in turn, leads to an increase in the growth of salmon. Ten years ago, the average sockeye harvest on the Pilgrim River was 2,000 salmon, supporting a small subsistence fishery. The average harvest from 2003 to 2008 was 10,000 salmon, a five-fold increase, and returns increased to as many as 90,000 sockeyes. Since 2008, the returns have fallen dramatically. It appears that fertilization was too successful and too many salmon were returning to Salmon Lake, where competition for food led to low survival of the juveniles in the lake. Our goal is to re-create conditions that will support an annual subsistence harvest of 10,000 sockeye salmon each year. In 2011, NSEDC plans to add 10 tons of fertilizer to Salmon Lake during the summer months; this is a quarter of the amount of fertilizer that led to too many salmon returning to the lake. We continue to monitor nutrient and zooplankton levels as well as other characteristics of Salmon Lake. For more information contact:
Norton Sound Economic Development Corporation
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