Pre- and post-hurricane assessment of artificial reefs: evidence for potential use as refugia in a fishery management strategy

Abstract

On 3 August and 4 October 1995, Hurricanes Erin and Opal, respectively, passed directly over Pensacola, Florida in the Northern Gulf of Mexico. After the hurricanes, fishers and divers could not relocate many artificial reefs in the area. Extensive visual censuses of artificial reef assemblages had been conducted in the impacted areas in 1991–1993. This database provided the opportunity to examine the effects of hurricanes on artificial reefs, and the interaction effects of hurricanes and fishing pressure on the associated fish assemblages. Post-hurricane positions of 38 reefs in a permitted reef site, 14 km offshore, were determined by sonar and identified visually by divers. Materials of higher density were least affected by wave surge; however, a large steel vessel was broken into several pieces. Lighter (low-density) materials were moved distances of at least 1000 m. Comparisons of pre- and post-hurricane fish assemblages revealed a significant increase in average length of gag ( Mycteroperca microlepis ) and red snapper ( Lutjanus campechanus ). Because some reefs were displaced, fishing pressure was greatly reduced for at least 1 year. The new coordinates for a number of the relocated reefs were released to the public, thereby subjecting the fish assemblages to increased fishing pressure. Pre- and post-fishing comparisons indicated significant differences in biomass, number of gray triggerfish ( Balistes capriscus ), average length of gag, and number and average length of red snapper. These results, coupled with published information, indicate that artificial reefs may serve as refugia from fishery harvest following severe storms. This refugia function has potential utility in the design of marine reserves as well as offering an alternative strategy in the development of fishery management plans. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved .