Relationship of Fish Mesohabitat to Flow in a Sand‐Bed Southwestern River

Abstract

We quantified the availability and utilization of habitat types by eight small-bodied cyprinid fish species, including the federally threatened Pecos bluntnose shiner Notropis simus pecosensis, in the Pecos River, New Mexico. The Pecos River is a medium-sized, sand-bed river with a highly variable hydrograph and some reaches characterized by historic and recent periods of flow intermittency. Fish habitat was described in four reaches at flows of 0.05-2.29 m 3 /s by means of a simultaneous, coordinated program of channel topographic surveys, mesohabitat mapping, fish sampling, and measurement of microhabitat and chemical parameters. We determined that fish habitat in this sand-bed river was effectively described at the mesohabitat scale. Furthermore, mesohabitats were visually distinguishable and separable by means of hydraulic and geomorphic parameters and the relationship between flow and depth, velocity, and velocity : depth ratios. The eight cyprinid species in the Pecos River primarily used four mesohabitat types that were consistently available at the full range of flows examined, including perpendicular and parallel plunges, backwaters, and slackwaters. In winter, five species (red shiner Cyprinella lutrensis, plains killifish Fundulus zebrinus, plains minnow Hybognathus placitus, Arkansas River shiner N. girardi, and sand shiner N. stramineus) shifted to backwaters, where water temperatures were relatively warmer than those of the main channel. Runs, flats, and riffles were generally the most available mesohabitat types, but their availability changed with flow; only four species (red shiner, plains killifish, speckled chub Macrhybopsis aestivalis, and sand shiner) selected these types, and they did so infrequently in summer. The Pecos bluntnose shiner was a habitat specialist that selected primarily rare plunge pools at sandbar faces, whereas species such as the red shiner were habitat generalists that used a variety of mesohabitat types. We found that a range of base flows sustained the preferred habitats of the eight cyprinid species and that no single flow maximized this preferred habitat because of a scaling effect of flow on sand bedforms.

The emblematic minnows of the North American Great Plains: A synthesis of threats and conservation opportunities

“… References: 1 Dudley and Platania (); 2 Welker and Scarnecchia (); 3 Pollard (); 4 Harrel, Davis and Dorris (); 5 Kilgore Jr. and Rising (1965); 6 Bonner, Wilde, Jimenez and Patiño (); 7 Kehmeier et al. (); 8 Heard et al. (); 9 Gido et al.…”

“…Western silvery minnow, plains minnow and Red River shiner were reported from backwaters, side channels, mainstream borders and depressional environments (Hesse, ; Houston, ; Kilgore & Rising, ; Welker & Scarnecchia, ). Conversely, sturgeon chub and Pecos bluntnose shiner were reported in swift velocity mainstem habitats (Kehmeier, Valdez, Medley & Myers, ; Ridenour, Starostka, Doyle & Hill, ; Welker & Scarnecchia, ). Despite the commonalities in mesohabitat, habitat partitioning between western silvery minnow and plains minnow has been observed at finer spatial scales.…”

Habitat associations of the sharpnose shinerNotropis oxyrhynchusin the upper Brazos River, Texas

“…For example, based on the univariate and bivariate habitat characteristics, Matthews and Hill (1980) and Polivka (1999) found evidence of nonrandom selection of microhabitats by the dominant cyprinid species in the South Canadian River, Oklahoma, but observed little consistency in the types of habitats used by these species. In contrast, Kehmeier et al (2007) reported that small-bodied cyprinids were nonrandom in their use of various habitat types in the Pecos River, New Mexico, but that there was substantial overlap among these habitats in physical and chemical characteristics. It remains unclear if fishes that inhabit the Great Plains streams and rivers have specific habitat requirements or preferences that, as yet, have not been definitively identified or if the inconsistent evidence for specific habitat associations reflects a generalist strategy among these species for coping with life in extremely variable environments.…”

Detection and Population Estimation for Small‐Bodied Fishes in a Sand‐Bed River

“…Although a few deeper pools were encountered outside the sample reaches, the majority of the river could be easily waded and seined. Most of the sampled sites contained five to six mesohabitat types (Kehmeier et al 2007), run and flat mesohabitat types being dominant throughout. Braided reaches contained higher habitat diversity than incised reaches; backwater and slackwater areas occurred along the shore and sandbar margins.…”

“…We evaluated the effectiveness of the removal by estimating numbers of small-bodied fishes at seven sites of the Pecos River between Sumner Dam and Brantley Reservoir ( Figure 1) during September 20-23, 2005. To provide a robust test of the removal method, we selected sites in areas with a representative suite of habitat features (e.g., backwater, flat, parallel plunge, perpendicular plunge, pool, riffle, run, and slackwater; Kehmeier et al 2007). Specific site length was determined by locations where block nets could be effectively set.…”