Habitat Associations, Life History and Diet of the Sabine Shiner Notropis Sabinae in an East Texas Drainage

Article excerpt

ABSTRACT.-

We examined aspects of the ecology of Notropis sabinae, the Sabine shiner, including habitat associations, population age structure, reproduction and diet in two east Texas streams from November 2001 through October 2002. Notropis sabinae exhibited no strong seasonal habitat associations, but generally were found in relatively shallow slow flowing runs and riffles. The population consisted of three age groups (ages 0, 1, 2) with age-1 fish being the most abundant. Estimated maximum life span was 2.5 y. Reproductively mature individuals were observed from May through October. Temporal patterns in ovarian development, gonadosomatic index and ova development indicated that N. sabinae spawns multiple clutches of eggs over an extended spawning period. Stomach contents consisted primarily of aquatic insects, followed by other aquatic taxa (e.g., Collembola, Crustacea and Hydracarina) and terrestrial insects.

INTRODUCTION

Notropis sabinae, thé Sabine shiner, inhabits lotie environments ranging from small headwater streams to large rivers. Populations can be found from the San Jacinto drainage of eastern Texas and eastward through central Louisiana to the Big Black and Yazoo drainage systems of Mississippi (Douglas, 1974; Hubbs et al., 1991; Ross, 2001). In addition, northern populations disjunct from the gulf coast drainages exist in three river systems (White, Black and St. Francis rivers) in northern Arkansas and southern Missouri (Gilbert, 1978; Robison and Buchanan, 1988). Although Warren et al. (2000) consider this species to be currently stable, JV. sabinae was designated as a species of conservation concern in Texas and Louisiana by the U.S. Forest Service Region 8 and U.S. Fish and Wildlife Service Region 2, and as a species of special concern in Mississippi (Ross, 2001).

Information on the ecology of Notropis sabinae is limited to only a few investigations. These studies indicate that JV. sabinae is a benthic species that uses habitat with sandy substrate and moderate current velocities with abundances ranging from rare to common (Gilbert, 1978; Moriarty and Winemiller, 1997; Ross, 2001). In Sabine River tributaries of Texas and Louisiana, reproduction takes place from April through September with multiple egg clutches spawned by 1 to possibly 3 y old females; maximum standard length is 49 mm (Heins, 1981). Little additional information is available about temporal trends in habitat associations and population age structure of JV. sabinae within the streams it inhabits. Herein, we provide information concerning aspects of the life history of JV. sabinae from a stream system (Banita Creek and LaNana Bayou, Nacogdoches County, Texas) that historically (Dickens, 1950) and presendy supports a large population of this species. Specifically, we sought to assess habitat associations, number of age groups present, longitudinal distribution, gonadal maturation, sex ratio and food habits of the JV. sabinae population in this stream system.

METHODS

Banita Creek and LaNana Bayou (Nacogdoches County) are tributaries of the Angelina River in east-central Texas. Both streams originate north of Nacogdoches, Texas and flow south until merging near the southern extent of the city. Both are perennial, shallow streams with silt, sand and bedrock substrates. Channel geomorphic units (Goldstein and Meador, 2004) range from swift flowing bedrock chutes and riffles to slow flowing runs and pools. In some reaches, concrete and other debris associated with municipal streams (e.g., discarded tires and furniture) are common. Riparian areas and watersheds are used primarily for urban or agricultural purposes.

Sampling methodology.-We collected quantitative and qualitative habitat information and fish monthly from November 2001 through October 2002 at three sites on Banita Creek and one site on LaNana Bayou. Collection sites were established at upstream (Site 1) and middle (sites 2 and 3) reaches of Banita Creek and downstream (Site 4) on LaNana Bayou. …