Topical application of hormone gonadotropin‐releasing hormone (GnRH‐A) stimulates reproduction in the endangered Texas blind salamander (Eurycea rathbuni)

Abstract

AbstractWe present a landmark success of a pilot study in the noninvasive, topical hormonal stimulation of reproduction of salamanders using Texas blind salamanders (Eurycea rathbuni) as a model species. Improved reproduction is a critical milestone in the conservation of imperiled species. Captive reproduction of amphibians is often challenging due to specific and ambiguous environmental cues for each species. The Texas blind salamander is a federally listed troglobitic amphibian found only in the Edwards Aquifer beneath San Marcos, Texas. This species is long‐lived, paedomorphic, and obligately aquatic. As with other cave‐dwelling organisms, Texas blind salamanders exhibits delayed reproductive maturity and low reproductive output. The US Fish & Wildlife San Marcos Aquatic Resources Center maintains a captive assurance population of wild individuals to supplement natural populations in the case of a catastrophic impacts on the wild population. Despite housing this species since the 1980s, unassisted reproductive events remain infrequent and unpredictable. In 2020, we developed the noninvasive use of the topical application of GnRH‐A to stimulate reproduction in 12 females combined with 12 males during a pilot study, that resulted in 11 clutches over a five‐month period. These findings mark a significant increase from normally low production of 4.5 clutches annually (average from 2007 to 2019) and represent a landmark success for captive propagation of this species.