Homing mechanisms and mating systems of Atlantic cod: evidence from a Newfoundland spawning ground

Abstract

This study investigates the movements of Atlantic cod (Gadus morhua L.) during the spawning season in Placentia Bay, Newfoundland, and consists of two components. First, transplantation techniques and acoustic telemetry are used to demonstrate that transplanted cod return more successfully to a spawning ground from a traditional migratory pathway compared to cod transplanted to a less-used area, suggesting that familiar landmarks are important to short-distance homing. Second, spatial and temporal patterns of fishing data and acoustic tracking of individual fish are used to document leklike behaviour of cod at a small-scale spawning ground, including spatial patterns of male-skewed sets, higher proportions of spawning females in male dominated aggregations, and highly mobile movements of cod over the grounds. The results offer insights into spatial learning in ocean migrants, and provide supportive evidence for lekking behaviour in wild cod populations.