Notropis oxyrhynchus

Taxon of unquestioned validity (Starnes 1995).

Small range, confined to streams in Texas; stable in the upper Brazos River basin, has declined in the middle and lower basin; threatened by impoundments and degradation of habitat by various human activities and invasive species.

The sharpnose shiner historically occurred throughout the Brazos River system, including the Double Mountain and Salt Forks of the Upper Brazos River drainage. Now it is very rare or possibly extirpated downstream of Possum Kingdom Reservoir (USFWS 2002). It has been documented in the South and North Forks of the Wichita River within the Red River Basin but has not been collected from the Wichita River drainage since the 1950s (Moss and Mayes 1993). An introduced population may exist in the Colorado River above Buchanan Reservoir (Hubbs et al. 1991); however, the validity of this population is still in question (e.g., Moss and Mayes 1993).

This species is represented by a small number of distinct occurrences (subpopulations) and locations (as defined by IUCN). It is known from a few dozen sites, including 24 sites upstream of Possum Kingdom Reservoir (Moss and Mayes 1993). Recently it was recorded at 10 of 13 sites sampled in the upper Brazos basin (Ostrand 2000). Additional collection efforts have produced few specimens in the middle and lower Brazos River (see USFWS 2011). Some of the collection sites mentioned above are not distinct occurrences or locations but rather represent portions of larger occurrences or locations.

USFWS (2011) summarized threats as follows:

The primary threat to the sharpnose shiner is habitat loss and modification due to current and future reservoir development. Reservoir development within the Brazos River Basin is largely responsible for the modification of habitat in the river that has rendered major portions unsuitable for the sharpnose shiner. The three major impoundments of the Brazos River proper have apparently extirpated the sharpnose shiner from the middle Brazos region and reduced it to relict populations within the lower portion of the river. Proposed reservoir development in the upper Brazos region is a significant threat to the extant populations. While only one reservoir is currently permitted (Post Reservoir) in the upper Brazos region, others are included in the Texas State Water Plan as a potential source to meet the demand for water through the year 2060.

Additional substantial threats to the sharpnose shiner are in-stream sand and gravel mining, industrial and municipal discharges, CAFOs, desalination, excessive sedimentation, and the spread of invasive saltcedar. The effect of saltcedar within the upper Brazos region threatens the existing sharpnose shiner habitat. Saltcedar encroachment in the upper Brazos and tributaries is likely an indirect result of impoundment of the river. Desalination is a potential future threat in the upper Brazos River Basin. In-stream sand and gravel mining, excessive sedimentation, and industrial and municipal discharges coupled with the effect of impoundments, reduce the likelihood of the Brazos River sustaining viable populations of the sharpnose shiner downstream of Possum Kingdom Reservoir. These threats combined with the substantial reduction in historic range due to anthropogenic factors justify the candidate status of the sharpnose shiner.