Author: Darin RuhlPublisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 82
Book Description
Concerns expressed by local subsistence users over declines in Afognak Lake sockeye salmon Oncorhynchus nerka production prompted the Alaska Department of Fish and Game to investigate Afognak Lake?s rearing environment beginning in 2003. Funded through the U.S. Fish and Wildlife Service Office of Subsistence Management, Alaska Sustainable Salmon Fund, and Kodiak Regional Aquaculture Association, this report provides results from the 2016 season. Based on established mark-recapture techniques, an estimated 227,178 sockeye salmon smolt outmigrated from Afognak Lake in 2016. From 2003-2015, the outmigration averaged 319,205 and ranged from 127,861 to 564,793 smolt. Age-1 smolt made up 93.6% of the outmigration in 2016 and averaged 76.9% of the outmigration from 2003 to 2015. Length, weight, and condition data indicate fairly healthy, robust Age-1. smolt over the fourteen years of the project with an average condition factor of 0.81. Limnological sampling was conducted during 5 monthly events from May to September in 2016. Phosphorus concentrations and zooplankton densities remained low, while chlorophyll-a levels were slightly above average. Nitrogen concentrations, lake temperatures, and phytoplankton biovolume were above average for the third consecutive year. Afognak Lake sockeye salmon returned in sufficient numbers to meet the escapement goal of 20,000?50,000 sockeye salmon while supporting subsistence, sport, and commercial harvests. The escapement of 33,167 fish in 2016 was slightly below the average of 41,479 sockeye salmon (2011?2015) and was predominately composed of age-1.3 and age-1.2 fish.