WASHINGTON (CN) - The U.S. Fish and Wildlife Service has proposed
two minnow species in Texas for endangered listing status under the Endangered Species Act (ESA). The agency also proposes 623 river miles of critical habitat for the fish in a separate action
The proposals were spurred by the 2011 settlement agreement between the USFWS and the Center for Biological Diversity (CBD), which resulted in a five-year work plan to speed listing decisions for hundreds of species across the nation. "The intent of the agreement is to significantly reduce litigation-driven workloads and allow the agency to focus its resources on the species most in need of the ESA's protections," the agency's press release stated.
The sharpnose shiner and the smalleye shiner are minnows that are now found in only one reach of the Brazos River in Texas. During Texas' "worst 1-year drought on record" in 2011, the Brazos River went dry, according to the action. Texas state fish biologists captured sharpnose and smalleye shiners from isolated pools and maintained them in captivity until the following year when they were released into the lower Brazos River. The agency noted that "a similar drought in 2012 would have likely led to extinction of both species."
The fish require unobstructed flowing water during the breeding season to successfully reproduce, as the eggs and larvae remain suspended in the water column until they mature enough to swim on their own. In still water, the eggs, larvae and immature fish sink to the bottom and die. "Experiments have shown that the fishes need flows of 92 to 227 cubic feet per second to reproduce. They also need at least 171 miles of undammed flowing water for the juveniles to reach maturity," the CBD noted in their statement.
"The naturally occurring historical distribution of the sharpnose shiner included the Brazos River, Colorado River, and Wichita River in Texas, while the naturally occurring historical distribution of the smalleye shiner included only the Brazos River," the action said. Because both species are reduced to only one viable population, the fish "lack redundancy." The USFWS defines redundancy as "the ability of a species to withstand catastrophic events by spreading the risk, and can be measured through the duplication and distribution of resilient populations across its range." Both minnow species also lack "resiliency," or the ability to withstand random events, and "representation," or the ability of the species to adapt to changing environmental conditions. Both of these hallmarks of species viability are determined by the extent of habitat.
The USFWS has proposed to designate 623 miles of the upper Brazos River basin, including the riparian areas extending 30 meters on each side beyond the river channel as critical habitat. The proposed habitat would wind through 11 Texas counties.
The 60-day comment period closes Oct. 7. A public information session and hearing will be held Sept. 4.