Fishes recorded in surveys of streams in Guanacaste Conservation Area (ACG)

Abstract

In March 2015, we visited ACG with the primary objective to characterize fish communities around Rincon de la Vieja National Park and other habitats. We were particularly interested in identifying sites that are characterized by high concentrations of hydrogen sulfide. We found two sulfide springs, but only one (Middle Earth; MT15-09) was inhabited by fish. Fish at each site were sampled with seines or a backpack electro-shocker, depending on the habitat. All species were identified on site based on keys provided by Bussing (1998). After photographing select specimens, fish were released unharmed at the original collection site. The exception included select specimens of the family Poeciliidae, which were fixed for morphological analyses as permitted by our permit. In the coming months, we will analyze morphological variation of Poecilia gillii collected at the Middle Earth site and compare it to specimens from adjacent, non-sulfidic habitats. Considering the similarity of the Middle Earth site to sulfide springs in Mexico, future research should include genetic analyses that test for genetic differentiation between sulfidic and non-sulfidic populations, which has been documented for sulfide spring species of the genus Poecilia in Mexico (Tobler & Hastings 2011; Tobler et al. 2011). Below we provide our data from sampling efforts during last month’s visit. For each site, we provide latitude and longitude, as well as a list of species detected. We also include photographs of habitats and select specimens that were seen at each site.