The Potential for Unreported Artificial Reefs to Serve as Refuges from Fishing Mortality for Reef Fishes

Abstract

Abstract This study tested the potential for 27 artificial reefs, which were deployed in the northeastern Gulf of Mexico (nGOM) but not reported to the public, to serve as refuges from fishing mortality for reef fishes. Red Snapper Lutjanus campechanus (n = 2,114) and Gray Triggerfish Balistes capriscus (n = 267) were tagged at a subset (n = 9) of the study reefs from winter 2005 to fall 2007 to estimate their site fidelity and mortality rates. Mortality was also estimated from catch curves fit to Red Snapper and Gray Triggerfish age distributions that were estimated at the study reefs both before (2005–2007) and after (2007–2008) the GPS coordinates of the above subset were advertised to the public. Red Snapper site fidelity (f), estimated by fitting Burnham's (1993) joint encounter model to tagging data, was 12.8% per year; while estimated instantaneous total mortality (Z) of Red Snapper ranged from 0.08 per year during the closed recreational fishing seasons to 1.31 per year during the open seasons. Similar estimates were not available for Gray Triggerfish due to inadequate model structure. Prior to reporting of reef coordinates to the public, estimated Z from the catch curve analysis was 1.04 per year for Red Snapper and 0.56 per year for Gray Triggerfish. After reporting, estimated Z increased from 0.56 to 0.69 per year for Gray Triggerfish and from 1.04 to 1.14 per year for Red Snapper. The low site fidelity and high fishing effort in the region resulted in no discernible refuge effects for Red Snapper. A modest refuge effect occurred for Gray Triggerfish, fish which have been shown to display high site fidelity (>80% per year) to reefs; however, Gray Triggerfish mortality from fishing quickly increased following the reporting of the study reef coordinates. Our study results indicate that unreported artificial reefs that are deployed in areas of the nGOM where fishing is otherwise allowed are not likely to offer protection to reef fishery species. Received November 14, 2014; accepted August 12, 2015