Fish community and trophic structure were examined quarterly from fall 2004 through spring 2007 at 27 artificial reef sites located 15-20 mi south of Pensacola, Florida. Location of study sites was not reported to the public when reef modules were deployed in 2003, thus sites were presumed to be unfished. Community structure estimates were derived from video sampling that was performed with a micro remotely operated vehicle (ROV) equipped with a laser scale to estimate fish size. A total of 81,207 individuals from 77 different taxa was enumerated from video samples. Fish assemblages were dynamic in species richness, fish community structure, and trophic structure across time and by reef design. Total fish density, biomass, and species richness increased across time. Red snapper, Lutjanus campechanus (Poey, 1860), was by far the most abundant species (29% of individuals, 45% of total biomass), and its density and biomass increased over the course of the study. Differences in fish community structure were driven by sharp declines in grouper abundance and the proliferation of smaller fishes across time. Trophic structure was consistently dominated by invertivore/piscivores, while fluctuation in piscivore biomass and increased abundance of planktivores drove differences in trophic structure. Size distributions for many fishery species known to display low annual site fidelity were composed primarily of young, sub-legal individuals. Disappearance with increasing fish size was likely due to shifting ontogenetic habitat requirements or exposure to high regional fishing mortality for species that displayed low annual site fidelity to study sites.

No abstract

Data from the Integrated Tracking of Aquatic Animals in the Gulf of Mexico (iTAG) network, and sister networks, were used to evaluate fish movements in the Florida Keys-an extensive reef fish ecosystem just north of Cuba connecting the Atlantic Ocean and Gulf of Mexico. We analysed ~2 million detections for 23 species, ranging from reef fish such as Nassau grouper (Epinephelus striatus, Serranidae) to migratory apex predators such as white sharks (Carcharodon carcharias, Lamnidae). To facilitate comparisons across species, we used an eco-evolutionary movement strategy framework that identified measurable movement traits and their proximate and ultimate drivers. Detectability was species-specific and quantified with a detection potential index. Life stages detected in the study area varied by species and residency varied with life stage. Four annual movement types were identified as follows: high site-fidelity residents, range residents, seasonal migrants and general migrants. The endangered smalltooth sawfish (Pristis pectinata, Pristidae), a seasonal migrant, exhibited the greatest within-ecosystem connectivity. Site attachment, stopover and deep-water migration behaviours differed between individuals, species and annual movement types. All apex predators were migratory. General migrants were significantly larger than fish in the other movement types, a life-history and movement trait combination that is common but not exclusive, as many small pelagics also migrate.Most teleosts exhibited movements associated with spawning. As concerns grow over habitat and biodiversity loss, multispecies movescapes, such as presented here, are expected to play an increasingly important role in informing ecosystem-based and non-extractive fisheries management strategies.

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

No abstract