The Herpetological Journal

pp.43-49

Authors: Luz Calia Miramontes Sequeiros, Nicolás Palanca Castán & Antonio Palanca Soler

Abstract: The introduction of non-native species is one of the factors driving the global decline of amphibians. We examined the
effect of fish stocking in naturally fishless mountain lakes and ponds on the local populations of the European common frog (Rana temporaria). We surveyed 215 mountain lakes and ponds and noted the presence or absence of frogs and signs of frog reproduction (i.e. tadpoles, eggs). We compared these data with fish stocking data from the regional park management (all surveyed lakes and ponds). Our results show a strong negative effect of fish stocking on the presence of R. temporaria, and an even stronger effect on its breeding presence, but we found a small number of lakes and ponds where coexistence occurred. In addition, the preferential stocking of large, deep lakes and ponds left smaller ponds as the only remaining habitats, a number of which are likely to become temporary due to increased summer temperatures. We recommend a series of measures to conciliate fish stocking for recreational fishing whilst conserving R. temporaria populations, which might be extensible to other high mountain environments.

Keywords: Fish stocking, Rana temporaria, Oncorhynchus mykiss, amphibian conservation, Pyrénées National Park