The Skeena Fisheries Commission, in cooperation with local First Nations and DFO, has been quantifying the number of age-0 sockeye fry rearing in various Skeena River Watershed lakes since 2006, using a scientific echo-sounder along with concurrent trawl and gillnet sampling. The latter is used to estimate the limnetic fish species composition in each lake, and is combined with geo-referenced acoustic data to produce age-0 sockeye fry population estimates and rearing densities, as well as estimates for competing limnetic species for each surveyed lake. The sockeye trawl and gillnet samples will also provide age and size data for the juvenile sockeye population at each lake. Each year, the program surveys 4 or 5 lakes in the Skeena River Watershed.
Sockeye from all of the selected lakes are harvested in both Canadian and American fisheries, and are therefore relevant to the Pacific Salmon Treaty. Hydroacoustic surveys are a cost effective method for assessing the status of sockeye stocks. Adult escapements for many BC north coast sockeye lakes are currently not determined due to high costs from the remoteness of the lake or due to other factors such as poor visibility for assessing lake spawners. The hydroacoustic methodology allows for a quick, accurate and cost effective assessment of the stock status of each surveyed lake. Fry surveys on lakes that have reliable estimates of adult escapement are useful for quantifying egg-to-fry survival, density dependent growth rates, and lake carrying capacity.