Stacey Lyn Harter

Abundance estimates of the Indo-Pacific lionfish Pterois volitans/miles complex in the Western North Atlantic

Less than a decade after being observed off Florida, the invasive Indo-Pacific lionfish is now widely distributed off the southeast coast of the United States. As a step towards measuring invasion impacts to native communities, we examine the magnitude and extent of this invasion by first, compiling reports of lionfish to provide range information and second, estimate lionfish abundance from two separate studies. We also estimate native grouper (epinepheline serranids) abundance to better assess and compare lionfish abundances. In the first study we conducted SCUBA diver visual transect surveys at 17 different locations off the North Carolina coast in water depths of 35–50 m. In the second study, we conducted 27 Remote Operated Vehicle (ROV) transect surveys at five locations from Florida to North Carolina in water depths of 50–100 m. In both studies, lionfish were found to be second in abundance only to scamp (Mycteroperca phenax). Lionfish were found in higher abundance in the shallower North Carolina SCUBA surveys (\(\bar{x}= 21.2\) ha−1) than in the deep water ROV surveys (\(\bar{x} = 5.2\) ha−1). Lionfish reports continue to expand most recently into the Bahamas, raising the specter of further spread into the Caribbean and Gulf of Mexico. The potential impacts of lionfish to native communities are likely to be through direct predation, competition and overcrowding. The high number of lionfish present in the ecosystem increases the potential for cascading impacts throughout the food chain. Within the southeast region the combined effects of climate change, overfishing and invasive species may have irreversible consequences to native communities in this region.

Fish assemblages associated with red grouper pits at Pulley Ridge, a mesophotic reef in the Gulf of Mexico

The views and opinions expressed or implied in this article are those of the author (or authors) and do not necessarily reflect the position of the National Marine Fisheries Service, NOAA. Abstract—Red grouper (Epinephelus morio) modify their habitat by excavating sediment to expose rocky pits, providing structurally complex habitat for many fish species. Surveys conducted with remotely operated vehicles from 2012 through 2015 were used to characterize fish assemblages associated with grouper pits at Pulley Ridge, a mesophotic coral ecosystem and habitat area of particular concern in the Gulf of Mexico, and to examine whether invasive species of lionfish (Pterois spp.) have had an effect on these assemblages. Overall, 208 grouper pits were examined, and 66 fish species were associated with them. Fish assemblages were compared by using several factors but were considered to be significantly different only on the basis of the presence or absence of predator species in their pit (no predators, lionfish only, red grouper only, or both lionfish and red grouper). The data do not indicate a negative effect from lionfish. Abundances of most species were higher in grouper pits that had lionfish, and species diversity was higher in grouper pits with a predator (lionfish, red grouper, or both). These results may indicate that grouper pits are a favorable habitat for both lionfish and native fish species or that the presence of lionfish is too recent to have caused changes to fish community structure. The red grouper (Epinephelus morio) has been harvested in the United States since the 1880s and is currently the most common grouper species landed in both commercial and recreational fisheries of the Gulf of Mexico (Fisheries Statistics Division, National Marine Fisheries Service, Annual Commercial Landing Statistics, website, and Saltwater Recreational Data and Statistics, website). Like other grouper species, the red grouper is a slow growing, late maturing, relatively stationary, and long lived fish (Moe1; Jory and Iversen2). Adult red grouper inhabit the deeper