Etheostoma segrex
Overview
The Río Salado darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the Río Salado and its tributaries in Mexico. It inhabits unvegetated river bottoms with moderate turbulence over gravel and small cobble substrate. This species can reach a length of 4.4 cm (1.7 in).
The Etheostoma segrex faces severe population decline due to habitat degradation from agricultural runoff and sedimentation in its limited stream systems. Dam construction and water diversions have altered natural flow regimes critical for spawning and feeding behaviors. Urban development within its watershed has increased pollution loads and reduced water quality, while invasive species compete for limited resources in its restricted range.
Habitat
This darter species inhabits clear, fast-flowing streams with rocky substrates and gravel beds typical of Appalachian headwater systems. It requires well-oxygenated waters with specific temperature ranges and depends on riffle areas for feeding on aquatic invertebrates.
