Determining the influence of abiotic factors on spatial–temporal patterns of marine catfish (family: Ariidae) within the Apalachicola Bay System, Florida

Two species of marine catfishes (family: Ariidae) are abundant within the Apalachicola Bay System for much of the year. They function as 2nd and 3rd order consumers and as prey for top predators. Males perform oral incubation, a trait of most ariid catfish species, and thus, unique considerations may be factored into conservation efforts. The purpose of this study was to reveal trends in catfish abundance and spatial distributions and identify the abiotic factors associated with these patterns. Data from fifteen years of monthly fishery-independent monitoring surveys performed by the Florida Fish and Wildlife Conservation Commission were used to examine catch per unit effort and an optimized hot spot analysis was used to observe spatial distributions. Boosted regression tree models were used to examine the relationship between abiotic factors and catfish abundance and movement. Both species co-occurred with overlapping distributions throughout most of the year and were most abundant prior to and during the spawning season in May through August. Hardhead catfish ( Ariopsis felis Linnaeus) were much more abundant than gafftopsail catfish ( Bagre marinus Mitchill) throughout the study. A migration event was observed for both gafftopsail catfish and hardhead catfish, likely in response to temperature changes. Boosted regression tree models revealed that salinity and water clarity were mainly influencing hardhead catfish distributions with temperature also being relevant throughout much of the year. Salinity was less influential for gafftopsail catfish which were mostly affected by water clarity and temperature. These results differ from observations of ariid catfish in tropical ecosystems in which ariid distributions are segregated and migration events occur twice a year and are salinity driven.