Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms

Wild fish aggregate at aquaculture net-pens, but the underlying mechanisms are not fully understood. This study examined how salmon farms attract coastal Atlantic cod Gadus morhua from their inshore spawning grounds. Acoustic receivers were deployed at 5 known cod spawning grounds and 6 salmon Salmo salar farms located at varying distances from these grounds in a mid-Norway study site. Cod were caught at each spawning ground annually from 2017-2019, fitted with acoustic transmitters and released (n = 535). A total of 289 tagged cod (54%) were detected at the salmon farms, with more cod detected at farms closest to the focal spawning grounds and at operational farms. The latter result is lik…