A Preliminary Analysis of Potential Hybridization between Gambusia nobilis and G. geiseri in a reconstructed desert wetland, San Solomon Cienega, Balmorhae State Park, Texas

Authors: Chad C. Hargrave

Year: 2010 (xlii)

Abstract

In an attempt to conserve two endangered fishes (Cyprinidon elegans and Gambusia nobilis), the Texas Parks and Wildlife Department (TPWD) restored a critical desert wetland habitat by creating the San Solomon Ciénega at Balmorhea State Park in 1996 through a cooperative effort among private, state, and federal entities. This re-creation of a desert wetland habitat within the boundaries of the original, natural ciénega provided critical habitat necessary for survival of desert wetland biota. As a result, the native fish fauna, including Cyprinidon elegans and Gambusia nobilis, have flourished, and this location now provides a natural habitat with the largest known concentration of these taxa. However, in addition to the endangered, native taxa, several invasive species also flourish in this restored cienega. One of these invasives, G. geiseri, is a congener to the endangered G. nobilis. During seasonal monitoring of the fish populations in this cienega, we noticed individuals that superficially have both G. nobilis and G. geiseri traits. These intermediate traits may suggest hybridization between these two species. I will report on a suite of meristic and morphometric data currently being collected, and present a statistical evaluation on the potential for hybridization between these species.