Effects of protection from fishing on the lengths of targeted and non-targeted fish species at the Houtman Abrolhos Islands, Western Australia

The effects of fishing and protection on the length of targeted and non-targeted warmtemperateand tropical reef fishes were studied using baited remote underwater stereo-videocameras at the Houtman Abrolhos Islands, Western Australia. Video images were obtained frominside a marine protected area (MPA) and from 3 replicate fished locations within each of 3 islandgroups. The effects of protection on the lengths of 6 targeted and 4 non-targeted fish species wereexamined. Five of the 6 targeted fish species were larger inside MPAs than in areas open to fishing(Choerodon rubescens, Lethrinus miniatus, Lethrinus nebulosus, Pagrus auratus and Plectropomusleopardus). Targeted species were, on average, 48 mm (10%) larger inside MPAs than in areas opento fishing. The vast majority of the individuals of C. rubescens, P. auratus and P. leopardus recordedwere smaller than their minimum legal size for first capture. For non-targeted species, only 1 of the 4,Coris auricularis, showed an effect of protection, with the mean length of individuals reduced by85 mm (33%) inside MPAs relative to areas open to fishing. This study demonstrated clear effects ofprotection from fishing on the size structure of populations of common warm-temperate and tropicalreef fishes.