Fisheries Research

Using acoustic telemetry to expand sonar escapement indices of Chinook salmon to in-river abundance estimates

Publication date: December 2019

Source: Fisheries Research, Volume 220

Author(s): Suzanne L. Maxwell, Greg B. Buck, April V. Faulkner

Abstract

Acoustic telemetry was combined with a project that uses sonar and drift gillnetting methods to estimate Chinook salmon Oncorhynchus tshawytscha escapement in the Nushagak River, Alaska. The sonar project uses dual-frequency identification sonars (DIDSONs) to count passing fish and drift gillnetting to apportion sonar estimates to species. These estimates are indices because the river’s width (∼300 m) and uneven bottom topography allow for only a third of the river to be sampled. This range is enough to fully enumerate sockeye salmon O. nerka, the dominate species, but not Chinook salmon, which are known to migrate beyond the sampling range. Acoustic telemetry was used to determine what proportion of Chinook salmon traveled within the sampling range of the sonar project. We inserted acoustic tags into Chinook salmon ∼13 km downriver and deployed an array of acoustic receivers at the sonar site to track tagged fish. From 2011 to 2014, 799 Chinook salmon were tagged. The tagged fish used the entire river width while migrating through the acoustic array exhibiting a wide variety of behaviors that included moving straight through the array, making multiple up and down trips, holding, and crossing over from one side of the river to the other. On average, 57% of tagged fish traveled through regions sampled by the sonar with annual percentages of 65% (2011), 54% (2012), 64% (2013), and of 47% (2014). These proportions were used to expand the sonar-derived indices to in-river abundance estimates.

Graphical abstract

Glossaire technique

Art d'attribuer le nom scientifique correct à un spécimen.
Un acronyme dérivé de l'expression 'sound navigation and ranging' . la...