Long-term movement patterns of coastal cod (Gadus morhua)

Abstract

Movement patterns were studied by means of hydroacustic telemetry along the Norwegian Skagerrak coast. Ultrasonic transmitters was surgically implanted in 10 coastal cod, and released in the same area as they where caught. Their swimming behavior was continuously recorded for 45 days by means of a stationary positioning system. For another 128 days after the initial 45 days, they where tracked using a handheld hydrophone. During the study period three fish left the area after 40-50 days, three moved 2-6 km away from the releasing site, and the remaining four stayed within the area (<2 km from releasing point.) This may indicate a low rate of ranging for cod in this area, and a high degree of fidelity to their area of residency.