Abstract

Red Lionfish are an invasive species native to the Indo-Pacific that were first detected on the Atlantic coast of Florida in the 1990s and rapidly expanded its range into the Gulf of Mexico sometime between 2006-2010. Initial observations of Red Lionfish off the Alabama coast (2011) were followed by a rapid and dramatic increase in the frequency of occurrence as well as the density of Red Lionfish. As part of an annual large-scale, randomized survey of thousands of artificial reefs and natural hard bottom areas off the Alabama coast, we examine the habitats that Red Lionfish used and estimate the population of Lionfish within those habitats over the last decade. Lionfish density was much higher on artificial reefs than natural reefs. However, the considerable larger expanse of natural hard bottom habitats in our region resulted in a much larger population estimate of Red Lionfish in natural versus artificial reefs. At peak abundance (2014-2016), we estimated approximately 250,000 Red Lionfish of coastal Alabama with 80% of that population on natural hard bottom areas. Variability in abundance by artificial reef type was also evident with chicken transport devices (coups) having the highest density of Red Lionfish followed by prefabricated concrete pyramids and low relief concrete rubble having the lowest density. No Red Lionfish were detected on bottom areas without structure. We discuss our results in the context of informing future artificial reef deployments with regard to artificial reef type and spatial placement of reefs.