Laboratory studies of substrate and microhabitat selection in the southern cavefish (Typhlichthys subterraneus Girard)

Abstract– The southern cavefish ( Typhlichthys subterraneus Girard) is a small troglobitic fish found in a few disjunct populations in the central United States. Protecting and managing these populations requires a knowledge of southern cavefish microhabitat requirements, including their preference for substrate. We conducted tests of their preferences for cobble, gravel, pea gravel, and sand substrates in two-way and multiple choice experiments for extended periods using time-lapse video photography. Cobble proved to be the substrate these fish preferred to occur within. In nature, this preference may provide cavefish increased foraging opportunities and/or refuge from high flows associated with flooding. Our results indicate the need to (1) maintain coarse substrate as an integral part of cavefish habitats, and (2) direct cavefish censusing attempts towards such key areas.