The Effects Of Depth and Type Of Artificial Reef On CPUE and Counts Of Lutjanus Campechanus

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 reef sites, but in the last 50 years government programs and private fishers have placed numerous artificial reefs in Alabama’s designated artificial reef zone with the goal of increasing fisheries production.   In the present study, we examined the effects of reef depth and reef type on red snapper densities and catch-per-unit-effort (CPUE) through standardized survey methods. We used hook-and-line (HL), fish trap, and hydroacoustic and SCUBA visual surveys to estimate red snapper distributions on 4 types of artificial reefs: army tanks, pyramids, large ships, and small reefs (e.g. metal cages, pipelines).  Total red snapper densities from visual counts did not differ; however small red snapper were more abundant at shallower depths and on smaller artificial reefs.  Diver surveys showed similar red snapper size distribution compared to HL and fish trap. For all locations, HL caught significantly larger red snapper than fish trap. Hook-and-line CPUE was best explained by the interaction between depth and reef type.  There was an increase in CPUE as depth increased on most reef types (army tanks the exception).  Trap CPUE were significantly greater on small reef types compared to all other reef types.    Thus, both location and reef type need to be considered when analyzing reef fish surveys for future artificial reef placements and estimating stock size.