Successful eradication of the non-native loricariid catfish Pterygoplichthys disjunctivus from the Rainbow River, Florida

Abstract

Non-native Pterygoplichthys (Loricariidae) are increasingly introduced and established in tropical and subtropical regions worldwide. Florida (USA) has a long history of introduction of loricariid catfishes. These catfishes are of management concern, particularly when they occupy sensitive habitats such as springs and spring runs. Limiting introduction and spread is important because springs are among the most imperiled aquatic habitats in Florida and serve as thermal refuges in winter for Pterygoplichthys. Herein we report the only known eradication of an introduced loricariid catfish by direct human intervention and the only eradication of a non-native fish in Florida by means other than the fish toxicant rotenone. Vermiculated sailfin catfish (Pterygoplichthys disjunctivus) was first observed in the Rainbow River, Marion County, Florida in December 2002 but disappeared by March 2003. Occurrence was documented again in April 2006. Monthly surveys and removals were done and 28 individuals were removed from 2006 through 2008 by hand and fish spear. No additional individuals have been found since June 2008 and quarterly monitoring continues. Factors that facilitated the removal efforts included the springs’ protected status as a Florida Aquatic Preserve, on-going monitoring and control programs for invasive aquatic macrophytes, high water clarity, small numbers and spatial extent of observed Pterygoplichthys, relative isolation from other source populations, and little evidence of reproduction and recruitment. Decisions to undertake eradication or control programs for non-native fishes require consideration of the vulnerability of the site, spatial scale, habitat, interconnectivity with source populations, impacts of the non-native in the absence of management intervention, and available resources.