Fidelity of Red Snapper to Petroleum Platforms in the Northern Gulf of Mexico

摘要

The habitat value of petroleum platforms for red snapper, Lutjanus campechanus, is poorly understood. However, it is widely recognized that the presence of thousands of platforms in the northern Gulf of Mexico (GOM) has affected the distribution of red snapper by the addition of hard substrate habitat. We evaluated the habitat value of petroleum platforms by monitoring the fidelity of red snapper to these structures with acoustic telemetry. In May 2003, 125 red snapper were captured with hook and line at several platforms in a 35-km~2 portion of the South Timbalier oil and gas lease blocks, 50 km south of Port Fourchon, Louisiana. Following anaesthetization with MS-222, an individually coded acoustic pinger was surgically implanted into the peritoneal cavity of each specimen. After a short recovery period fish were released at five platforms in the study area. Presence of individual snapper was recorded with omnidirectional acoustic receivers attached to eight platforms. Red snapper exhibited little movement among platforms in the study area; however, logistic regression showed a high initial fidelity to release location which subsequently decreased over time. Therefore, site fidelity was estimated to be high in the short-term, but much lower in the long-term. However, study results were confounded by tag detection issues that may have resulted in long-term site fidelity being underestimated. Overall, estimates provided of red snapper fidelity to petroleum platforms should lead to more effectivemanagement of this species by adding to the knowledge of the function of platforms as habitat and their importance to the GOM red snapper population.