Skeena lakes juvenile sockeye hydroacoustic surveys

We propose to use hydroacoustic methodology combined with trawl and gillnet sampling to estimate the limnetic fish species composition in six Skeena River and Nass River watersheds lakes and to estimate the population and rearing densities of age-0 sockeye fry and competitor limnetic species at each surveyed lake. The sockeye trawl and gillnet samples will also provide age and size data for the juvenile sockeye population at each lake. For 2020, we propose to survey Azuklotz, Bear, Damdochax, Lakelse, McDonell, and Wiiminosik lakes.

Sockeye originating from the selected lakes are harvested in both Canadian and American fisheries, and thus 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 and accurate assessment of the stock status of each surveyed lake. For lakes where reliable estimates of adult escapement are available, hydroacoustic fry surveys are useful for quantifying spawner-to-fry productivity. Finally, the estimates of age-0 sockeye fry population can be compared to the lake carrying capacity for each lake.