William F. Patterson

An Ecosystem-Based Approach to Evaluating Impacts and Management of Invasive Lionfish

Species invasions in marine ecosystems pose a threat to native fish communities and can disrupt the food webs that support valuable commercial and recreational fisheries. In the Gulf of Mexico, densities of invasive Indo-Pacific Lionfish, Pterois volitans and P. miles, are among the highest in their invaded range. In a workshop setting held over a 2-week period, we adapted an existing trophic dynamic model of the West Florida Shelf, located in the eastern Gulf of Mexico, to simulate the lionfish (both species) invasion and community effects over a range of harvest scenarios for both lionfish and native predators. Our results suggest small increases in lionfish harvest can reduce peak biomass by up to 25% and also that reduced harvest of native reef fish predators can lead to lower lionfish densities. This model can help managers identify target harvest and benefits of a lionfish fishery and inform the assessment and management of valuable reef fish fisheries.

Impacts of the Deepwater Horizon oil spill evaluated using an end-to-end ecosystem model

We use a spatially explicit biogeochemical end-to-end ecosystem model, Atlantis, to simulate impacts from the Deepwater Horizon oil spill and subsequent recovery of fish guilds. Dose-response relationships with expected oil concentrations were utilized to estimate the impact on fish growth and mortality rates. We also examine the effects of fisheries closures and impacts on recruitment. We validate predictions of the model by comparing population trends and age structure before and after the oil spill with fisheries independent data. The model suggests that recruitment effects and fishery closures had little influence on biomass dynamics. However, at the assumed level of oil concentrations and toxicity, impacts on fish mortality and growth rates were large and commensurate with observations. Sensitivity analysis suggests the biomass of large reef fish decreased by 25% to 50% in areas most affected by the spill, and biomass of large demersal fish decreased even more, by 40% to 70%. Impacts on reef and demersal forage caused starvation mortality in predators and increased reliance on pelagic forage. Impacts on the food web translated effects of the spill far away from the oiled area. Effects on age structure suggest possible delayed impacts on fishery yields. Recovery of high-turnover populations generally is predicted to occur within 10 years, but some slower-growing populations may take 30+ years to fully recover.

Linear decline in red snapper (Lutjanus campechanus) otolith Δ14C extends the utility of the bomb radiocarbon chronometer for fish age validation in the Northern Gulf of Mexico

Linear decline in red snapper (Lutjanus campechanus) otolith DC extends the utility of the bomb radiocarbon chronometer for fish age validation in the Northern Gulf of Mexico Beverly K. Barnett*, Laura Thornton, Robert Allman, Jeffrey P. Chanton, and William F. Patterson III Panama City Laboratory, National Marine Fisheries Service, Southeast Fisheries Science Center, 3500 Delwood Beach Road, Panama City, FL 32408, USA Fisheries and Aquatic Sciences, University of Florida, 7922 NW 71st Street, Gainesville, FL 32653, USA Riverside Technology, Inc. 2950 East Harmony Road Suite 390, Fort Collins, CO 80528, USA Earth, Ocean and Atmospheric Science, Florida State University, 117 N Woodward Avenue, Tallahassee, FL 32306, USA *Corresponding author: tel: þ850 234 6541 x232; fax: þ850 235 3559; e-mail: beverly.barnett@noaa.gov.

Feeding ecology of invasive lionfish (Pterois volitans and Pterois miles) in the temperate and tropical western Atlantic

Numerous location-based diet studies have been published describing different aspects of invasive lionfish (Pterois volitans and Pterois miles) feeding ecology, but there has been no synthesis of their diet composition and feeding patterns across regional gradients. 8125 lionfish stomachs collected from 10 locations were analyzed to provide a generalized description of their feeding ecology at a regional scale and to compare their diet among locations. Our regional data indicate lionfish in the western Atlantic are opportunistic generalist carnivores that consume at least 167 vertebrate and invertebrate prey species across multiple trophic guilds, and carnivorous fish and shrimp prey that are not managed fishery species and not considered at risk of extinction by the International Union for Conservation of Nature disproportionately dominate their diet. Correlations between lionfish size and their diet composition indicate lionfish in the western Atlantic transition from a shrimp-dominated diet to a fish-dominated diet through ontogeny. Lionfish total length (TL) (mm) was found to predict mean prey mass per stomach (g) by the following equation mean prey mass =0.0002*TL1.6391, which can be used to estimate prey biomass consumption from lionfish length-frequency data. Our locational comparisons indicate lionfish diet varies considerably among locations, even at the group (e.g., crab) and trophic guild levels. The Modified Index of Relative Importance developed specifically for this study, calculated as the frequency of prey a × the number of prey a, can be used in other diet studies to assess prey importance when prey mass data are not available. Researchers and managers can use the diet data presented in this study to make inference about lionfish feeding ecology in areas where their diet has yet to be described. These data can be used to guide research and monitoring efforts, and can be used in modeling exercises to simulate the potential effects of lionfish on marine food webs. Given the large variability in lionfish diet composition among locations, this study highlights the importance of continued location-based diet assessments to better inform local management activities.

Correction to: DNA barcoding significantly improves resolution of invasive lionfish diet in the Northern Gulf of Mexico

In the original publication, the Acknowledgements section has been published incorrectly. The corrected Acknowledgements is given in this correction:

Genotyping confirms significant cannibalism in northern Gulf of Mexico invasive red lionfish, Pterois volitans

DNA barcoding is used in a variety of ecological applications to identify organisms, including partially digested prey items from diet samples. That particular application can enhance the ability to characterize diet and predator–prey dynamics but is problematic when genetic sequences of prey match those of consumer species (i.e., self-DNA). Such a result may indicate cannibalism, but false positives can result from contamination of degraded prey samples with consumer DNA. Here, nuclear-encoded microsatellite markers were used to genotype invasive lionfish, Pterois volitans, consumers and their prey (n = 80 pairs) previously barcoded as lionfish. Cannibalism was confirmed when samples exhibited two or more different alleles between lionfish and prey DNA across multiple microsatellite loci. This occurred in 26.2% of all samples and in 42% of samples for which the data were considered conclusive. These estimates should be considered conservative given rigorous assignment criteria and low allelic diversity in invasive lionfish populations. The highest incidence of cannibalism corresponded to larger sized consumers from areas with high lionfish densities, suggesting cannibalism in northern Gulf of Mexico lionfish is size- and density-dependent. Cannibalism has the potential to influence population dynamics of lionfish which lack native western Atlantic predators. These results also have important implications for interpreting DNA barcoding analysis of diet in other predatory species where cannibalism may be underreported.

Experimental assessment of circle vs. J hook performance and selectivity in the northern Gulf of Mexico recreational reef fish fishery

Experimental assessment of circle vs. J hook performance and selectivity in the northern Gulf of Mexico recreational reef fish fishery Steven B. Garner*, William F. Patterson III, and Clay E. Porch Marine Sciences, University of South Alabama and Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA University of Florida, Fisheries and Aquatic Sciences, 7922 NW 71st Street, Gainesville, FL 32653, USA Sustainable Fisheries Division, National Marine Fisheries Service, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, FL 33149, USA *Corresponding author: tel: þ850-774-1936; e-mail: steve.garner.disl@gmail.com