Site fidelity and movement of adult Atlantic cod Gadus morhua at deep boulder reefs in the western Gulf of Maine, USA

摘要

Little is known about the role that patterns of habitat selection play in mediating movement of Atlantic cod Gadus morhua, particularly in off-shore environments. We used acoustic telemetry to study the movement of adult cod tagged at deep boulder reefs (DBRs) in the western Gulf of Maine. The movement of 65 cod tagged with acoustic transmitters was monitored by acoustic receivers deployed on the seafloor at 4 DBRs from May to September 2002 and September 2004 to February 2005. Each receiver encompassed an area of the seafloor of approximately 0.5 km2, and data on each fish were recorded for up to 95 d post-release. Twenty-three cod (35.4 % of tagged fish) exhibited high site fidelity to the DBR where they were caught and released (recorded in ＞ 82 % of the 1 h time bins), while 33 cod (50.8% of tagged fish) appeared to depart the area rapidly following release (recorded in ＜ 20 % of the 1 h time bins). Cod with high site fidelity exhibited no pattern of diel activity. Cod movement among DBRs was recorded in both sampling periods (maximum linear distance of at least 24 km). Patterns of site fidelity and movement did not differ significantly with fish total length, among individual DBRs, or between sampling periods. Understanding the spatial dynamics of fish populations with both resident and transient components that are linked to particular habitats can aid in development of unique management strategies for both sustainable fisheries and conservation of biological diversity.