Depth and Artificial Reef Type Effects on Size and Distribution of Red Snapper in the Northern Gulf of Mexico

Abstract

The Red Snapper Lutjanus campechanus is a highly exploited commercial and recreational species that dominates the artificial reef systems in the northern Gulf of Mexico. Off coastal Alabama there are few natural reefs, but in the last 50 years government programs and private fishers have placed numerous artificial reefs in the northeast Gulf of Mexico with the goal of increasing fisheries production. We examined the effects of artificial reef depth and reef type on Red Snapper densities and size distributions. We used hook-and-line, fish trap, and scuba visual surveys to estimate Red Snapper densities on four types of artificial reefs: army tanks, pyramids, small reefs (e.g., metal cages, pipelines), and large reefs (e.g., ships, dry docks, oil platforms). Small Red Snapper (<33 cm TL) were significantly more abundant at shallower depths (<35 m) and on small artificial reefs. Army tanks showed significantly more large fish (>33 cm TL) at shallow sites (<35 m) than at deeper sites (>35 m); in contrast, pyramids showed significantly more large fish at deeper sites. Ontogenetic habitat shift and fishing mortality were the most likely factors that would explain these Red Snapper distributions. Worldwide, artificial reefs are being used to enhance fishery resources and for habitat restoration. We document the importance of reef design and deployment location for Red Snapper, as well as the need for future artificial reef deployments to consider the relevant variables that affect the species that managers are attempting to enhance.

Received May 4, 2014; accepted October 20, 2014

ACKNOWLEDGMENTS

We thank M. Albins, R. Brewton, L. Grove, J. Herbig, D. Horn, P. Mudrak, C. Roberts, and J. Williams assistance in the field and laboratory. This project was funded by British Petroleum. This manuscript is a contribution of the Alabama Agricultural Experiments Station and the School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University.