Unlike other salmon species, sockeye salmon require a lake habitat during the juvenile phase of their life-cycle. Thus, 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 in the from 1994 to 1996. This study was used as a basis for determining appropriate fertilization levels for the lake.

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 2000 salmon; this supported a small subsistence fishery. The average harvest from 2003 to 2008 was 10,000 salmon, a five-fold increase. 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 2010, NSEDC is adding 18 tons of fertilizer to Salmon Lake during the summer months; this is less than half the amount of fertilizer that led to too many salmon returning to the lake. We are also studying the nutrient levels of the lake and their effects on both phytoplankton and zooplankton.

For more information contact:

Charlie Lean
NSFR&D Director

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Norton Sound Economic Development Corporation
420 L Street, Suite 310, Anchorage, AK 99501, Phone 1-907-274-2248, Fax 1-907-274-2249