Preservation of behavior after fifteen years of isolation: comparisons of wild and captive endangered pupfish in their natural habitat

Endangered species are often maintained in captivity to serve as a safeguard in the event of an extirpation of natural populations. However, wild and captive populations can rapidly diverge in genetic and phenotypic characteristics, including behavior, when maintained in isolation and under different environmental conditions. Here, we compare two populations of the endangered Leon Springs pupfish (Cyprinodon bovinus): a captive population maintained at the Southwestern Native Aquatic Resources and Recovery Center (SNARRC) and the only remaining wild population. Wild fish in the natural Texan Diamond Y desert spring are remnants of a past reintroduction of captive SNARRC fish, which occurred in 1998. The fifteen years of isolation have led to genetic and morphologic differences between the two populations. To assess the behavioral implications of such divergence, we released previously captive C. bovinus into natural habitat and quantified behaviors under natural conditions and in semi-controlled mesocosms and then replicated these conditions with the established natural population. Both populations exhibited similar levels of reproduction, foraging, and agonistic behavior. Despite divergence in genetic and morphometric characteristics, overall behavioral patterns of C. bovinus remained consistent in similar environments. This stability suggests that captive C. bovinus could again be successful establishing in their natural habitat. It is our hope that this investigation will help focus future conservation efforts towards monitoring the persistence of reintroduced C. bovinus in addition to providing a framework for other recovery plans reintroducing captive stock into ancestral habitats.