TPWD News Release — Jan. 20, 2004
The San Felipe gambusia (Gambusia clarkhubbsi), was discovered and described by Gary P. Garrett, Ph.D., of the Texas Parks and Wildlife Department and Robert J. Edwards, Ph.D., of the University of Texas-Pan American in Edinburg, in their article titled, "New species of Gambusia (Cyprinodontiformes: Poeciliidae) from Del Rio, Texas."
Scientists say the discovery of the fish is likely linked to an innovative plan by the City of Del Rio and a local country club golf course to improve and protect aquatic habitat along San Felipe Creek in Del Rio. They believe that as enhanced vegetation and more environmentally friendly approaches to creekside land management have been introduced, aquatic habitat has improved, causing native fish populations to rebound and become more widespread and visible.
New descriptions of vertebrates, especially within the U.S., are very rare. The new species joins the 30 other species of Gambusia which have a mostly subtropical distribution, including nine species which have been known to inhabit Texas waters. The recent find of a new species is remarkable since the state and the type locality, in San Felipe Creek, have been relatively well-sampled by scientists.
The last new fish species discovery in the state happened more than 30 years ago, when a species in the same genus was found to inhabit the San Marcos River in Central Texas. While that species is now extinct, the new species in Del Rio is abundant and is doing well, although this is the only place in the world were they are known to live.
The new species belongs to a group of fishes called mosquitofish, named because they consume vast quantities of mosquito larvae and are instrumental in the control of mosquito-borne disease vectors. They have been introduced world-wide as mosquito control agents. The adults of this new species are typically one inch long and female adults are about an inch-and-a-half long.
The species was named in honor of Clark Hubbs, an emeritus-Professor at the University of Texas at Austin, not only for his long-standing interest in this group of fish but also for his long involvement in the conservation of rare Texas fish.
The San Felipe Springs which feed the creek, inside the city of Del Rio, are the third largest springs in Texas, and the new species is a characteristic type of fish that depends upon spring water sources.
The discovery is thought to be related to two recent events. It is believed that the species was once restricted to very limited habitats until the city of Del Rio and the local golf course initiated proactive changes in land use operations around the San Felipe headsprings and creek in 1997. Also, a major flood in 1998 scoured the stream. These two factors in combination apparently removed impediments to the abundance of the species, leading to its discovery.
Garrett and Edwards have long histories of involvement in fish conservation in Texas and the Southwest. Edwards is currently the Team Leader of the U.S. Department of the Interior’s San Marcos and Comal River and Associated Ecosystems Recovery Team, the Team Leader of the Rio Grande Silvery Minnow Recovery Team, and a member of the Rio Grande Fishes Recovery Team. Garrett is also a member of each of these teams and is one of the Texas Parks and Wildlife Department’s major research scientists. Endangered species recovery teams are legislative-mandated groups of biologists which have the responsibility of providing the U.S. government with guidance about how to best conserve endangered species and the ecosystems on which they depend.