DISTRIBUTION AND HABITAT USE OF THE ARKANSAS RIVER SHINER IN THE NORTH CANADIAN RIVER, OKLAHOMA

Transcription

1 DISTRIBUTION AND HABITAT USE OF THE ARKANSAS RIVER SHINER IN THE NORTH CANADIAN RIVER, OKLAHOMA Gene R. Wilde Department of Range, Wildlife, and Fisheries Management Texas Tech University Lubbock, TX Final Report Submitted to: U.S. Army Corps of Engineers Tulsa, District 1645 S. 101 E. Avenue Tulsa, OK July 2002

2 In the last century, streams and rivers of the Arkansas River drainage of Arkansas, Colorado, Kansas, New Mexico, Oklahoma, and Texas were profoundly altered by water diversions and irrigation withdrawals, and by construction of at least 50 major reservoirs within the basin (Cross and Moss 1987; Limbird 1993). Historically, these streams were characterized as harsh environments, with erratic summer flows and extremely variable physical and chemical conditions (Cross and Moss 1987; Matthews 1987). Reservoir construction, in particular, has reduced both the magnitude and variability of stream discharge (Cross and Moss 1987; Pflieger and Grace 1987; Bonner and Wilde 2000). Reduced discharge can result in changes in channel morphology, reducing multiple braided-channels to a single channel (Williams and Wolman 1984; Friedman et al. 1998), and allow establishment of woody streamside vegetation (Stinnett et al. 1988), which can indirectly affect stream fish populations (Patton and Hubert 1993; Wilde and Bonner 2000). Associated with these changes in stream discharge and morphometry have been dramatic declines in the distribution and abundance of several native stream fishes (Cross and Moss 1987; Matthews 1987; Pflieger and Grace 1987; Limbird 1993). The Arkansas River shiner (Notropis girardi), flathead chub (Platygobio gracilis), peppered chub (Macrhybopsis tetranema), and plains minnow (Hybognathus placitus), which are obligate riverine species (Holden 1979), are among those species that have shown the greatest declines in distribution and abundance (Cross et al. 1983; Cross and Moss 1987; Pflieger and Grace 1987; Pigg 1991; Limbird 1993). The North Canadian River rises on the eastern slopes of the Sangre de Christo Mountains of northeastern New Mexico and flows 1,219 km east through New Mexico and Texas to its confluence with the Canadian River in eastern Oklahoma (Sublette et al.

3 1990; Pigg et al. 1992). The river is referred to as the Beaver River upstream from its confluence with its major tributary, Wolf Creek, in Oklahoma. The North Canadian River drainage was been extensively modified; there are six major reservoirs in the drainage, all in Oklahoma, four on the mainstem river and two on tributaries (Pigg et al. 1992; Limbird 1993). Mainstem reservoirs include Lake Optima on the Beaver River, Texas County, impounded in 1966; Canton Lake in Blaine County, impounded in 1948; Lake Overholser in Oklahoma County, impounded in 1919; and Lake Eufaula in McIntosh County, impounded in 1964, and which inundates the confluence of the North Canadian and Canadian rivers. Wolf Creek, the major tributary to the North Canadian River was impounded in Woodward County in 1938 to form Fort Supply Lake. Reservoir construction and water withdrawals within the North Canadian River drainage have resulted in a decreased magnitude and variability in stream discharge, and a narrowing of the stream channel (Williams and Wolman 1984; Friedman et al. 1998), which has affected fish populations within the drainage (Pigg et al. 1982; Larson et al. 1991; Luttrell et al. 1999; Pigg et al. 1999). In particular, there has been a substantial decrease in the distribution and abundance of the Arkansas River shiner (Notropis girardi), a Federally-listed Threatened Species, within the North Canadian River drainage (Larson et al. 1991; Pigg et al. 1999). The purposes of this study were: 1) to document the distribution and relative abundance of fishes, with special emphasis on the Arkansas River shiner, in the North Canadian and Beaver rivers, between Lake Optima and Canton Lake; 2) document microhabitat selection by stream fishes in this reach of the North Canadian River; and 3)

4 assess the suitability of the North Canadian River as habitat for the Arkansas River shiner. METHODS The fish assemblage of the North Canadian and Beaver rivers, between Optima and Canton reservoirs, was sampled on 5-7 July 2000 and August During both surveys fishes were sampled at 10 sites (Table 1), four in the North Canadian River and six in the Beaver River to assess abundance, composition, and distribution of fishes within these rivers. Each site was seined, using a 1.8 x 3.7-m (0.5- mm mesh) seine, for 30 to 45 minutes in an attempt to sample all possible habitat types. To assess habitat availability and selection, I sampled the fish assemblages of the North Canadian River at two sites (Sites 1 and 4, Table 1) and the Beaver River at one site (Site 6, Table 1). At each sampling site, on each date, ten to 15 transects, perpendicular to the main channel of the river, were established such that no two transects were located within 20 m of each other. One to five non-overlapping seine hauls were made across each transect. Matthews and Hill (1979; 1980) suggested that 50 seine hauls and associated habitat information were adequate to characterize habitat availability and preferences at a site. Transects were sampled in a downstream-upstream sequence to minimize impacts on adjacent transects (Matthews and Hill 1979). Fish were sampled with a 1.8 x 3.7-m (0.5- mm mesh) seine. Each seine haul covered a distance of 5 m and was made in a downstream direction, with the current, over homogenous habitat (Matthews and Hill 1979). After each seine haul was completed, captured fishes were identified, enumerated, and released. At the center of the area sampled, I recorded habitat

5 type (i.e., pool, backwater, main channel), substrate type, percentage of the transect in shade, percentage of the transect with cover, current velocity, turbidity, stream depth, channel width, and physicochemical data (temperature, conductivity, dissolved oxygen concentration, and ph) were recorded. In addition, I calculated stream discharge (m sec - 1 ) for each sampling site as the product of stream depth, channel width, and current velocity. Statistical analyses were conducted using SAS version 8.0 (SAS Institute Inc., 1999) and PC-ORD version 4.01 (McCune and Mefford 1999). RESULTS Twenty-seven species of, representing eleven families, were collected fish during 2000 and 2001 from the North Canadian and Beaver rivers. The most speciose groups were the minnows (Cyprinidae), represented by eight species, and sunfishes (Centrachidae), represented by six species (Tables 2-5). At all sample sites, in both years, the fish assemblage was numerically dominated by red shiner (Cyprinella lutrensis) (0 to 81% of the assemblage), fathead minnow (Pimephales promelas) (0 to 43%), sand shiner (Notropis stramineus) (0 to 48%), plains killifish (Fundulus zebrinus) (0 to 79%), and mosquitofish (Gambusia affinis) (0 to 90%). In general, red shiner and fathead minnow dominated the North Canadian River fish assemblage, whereas sand shiner, plains killfish, and mosquitofish dominated the fish assemblage of the Beaver River (Tables 2 and 3). Canonical correspondence analysis was used to explore the relationship between fish assemblage structure and environmental conditions for the 11 most common species (other species were too infrequently collected to include in the analysis). Environmental

6 variables explained a significant proportion of the variance in fish assemblage structure, with the eigenvalues of the first two canonical axes explaining 44.2% and 19.4% (combined = 63.6%), respectively, of the variation in fish abundance among samples. In general, gizzard shad (Dorosoma petenense), Mississippi silverside (Menidia beryllina), channel catfish (Ictalurus punctatus), bullhead minnow (Pimephales vigilax), red shiner, mosquitofish, and bluegill (Lepomis macrochirus), were most abundant in shaded, deep, wide stream-reaches characterized by low conductivity (Figure 1). In contrast, fathead minnow, sand shiner, suckermouth minnow (Phenacobius mirabilis), and plains killifish were more common in shallow, narrow stream-reaches characterized by high conductivity and a greater amount of in-stream cover (Figure 1). These differences in fish assemblage composition and structure reflect habitat differences between the North Canadian and Beaver rivers. Means of environmental variables on each sampling date are presented in Table 6.

7 DISCUSSION Distribution and composition of the fish assemblages of the North Canadian and Beaver rivers was similar to that described by Pigg et al. (1992). Of the 27 species of fishes collected from the North Canadian and Beaver rivers in this study, all except two previously have been reported from the North Canadian River Basin (Pigg et al. 1992). The two included one specimen of bigscale logperch (Percina macrolepida) and 28 specimens of blacktail shiner (Cyprinella venusta) from the North Canadian River just upstream from Canton Reservoir (Site 1). One specimen of bigscale logperch was preserved, but no specimen of blacktail shiner was preserved. No Arkansas River shiner was encountered during this study. Pigg (1991) and Pigg et al. (1992) reported that the Arkansas River shiner was last collected from the North Canadian River in The species remains common in the Canadian River (New Mexico, Oklahoma, and Texas) (Larson et al. 1991;Pigg et al. 1999; Bonner and Wilde 2000; Wilde et al. 2000), where it is tolerant of a wide range of environmental conditions (Matthews 1987; Polivka 1999; Wilde et al. 2000); however, the Arkansas River shiner appears to select habitat based on depth and current velocity (Matthews and Hill 1980; Polivka 1999; Wilde et al. 2000). As an initial assessment of the suitability of the North Canadian and Beaver rivers as habitat for the Arkansas River shiner, current and depth conditions were compared at the three sampling sites with comparable habitat measurements made in the Canadian River, New Mexico and Texas, in (Wilde et al. 2000).

8 In the Canadian River, approximately 25% of measurements were made in habitats with a current velocity of 5 to 15 cm sec -1 ; 35% of samples which contained Arkansas River shiner were made in habitats with these same currents (Figure 2). Similarly, 55% of current measurements were less than 40 cm sec -1 while 69% of samples that contained Arkansas River shiner were made in such habitats. This suggests a preference, by the Arkansas River shiner, for habitats with currents between 0 and 40 cm sec -1, with greater evidence for selection of habitats characterized by slower current velocities (< 20 cm sec -1 ). In the North Canadian and Beaver rivers, 64% to 78% of measurements of current velocity were made in habitats with currents less than 40 cm sec -1 ; however, fewer than 20% of measurements were made in habitats with currents less than 20 cm sec -1 (Figure 2). In the Canadian River, approximately 63% of measurements were made in habitats with a depth of 5 to 15 cm; 65% of samples that contained Arkansas River shiner were made in habitats with these same depths (Figure 3). This suggests a preference, by Arkansas River shiner, for habitats with depths between 0 and 20 cm. In the North Canadian River, 31% to 48% of measurements of stream depth were made in habitats with depths less than 20 cm. In the Beaver River, 79% of measurements of stream depth were made in habitats with depths less than 20 cm. In general, the North Canadian River provides habitat that is swifter and, especially, deeper than that selected by the Arkansas River shiner in the Canadian River, New Mexico and Texas. The Beaver River provides, on average, habitats with slightly greater currents velocities than those selected by Arkansas River shiner, but which are comparable in depth. Channel narrowing in the North Canadian and Beaver rivers,

9 resulting from reservoir construction and operation (Williams and Wolman 1984), may have resulted in a deepening of the river channel and an increase in current velocities. These comparisons suggest that the North Canadian and Beaver rivers may not currently provide adequate habitat for the Arkansas River shiner; however, they do not constitute a demonstration that a lack of adequate habitat is responsible for the absence or scarcity of this species in the North Canadian River drainage. In addition to habitat availability, other factors, particularly reproductive failure, are likely to contribute to the scarcity (absence) of the Arkansas River shiner in the North Canadian River drainage. The Arkansas River shiner is a member of a guild of prairiestream fishes that spawns semi-buoyant pelagic ova (Platania and Altenbach 1998). The ova require flowing water to keep them suspended in the water column until hatching occurs and young are strong enough to leave the current (Moore 1944; Bottrell et al. 1964). Wilde et al. (2000) suggested that an unimpounded stretch of river approximately 220 km may be necessary for the Arkansas River shiner to complete its life cycle. The North Canadian and Beaver rivers, between Lake Optima and Canton Lake, provide a longer continuous stretch of unimpounded river; however, stream discharge, particularly in the Beaver River, may not be sufficient to keep ova and young fish suspended in the water column. ACKNOWLEDGMENTS I thank B. Durham, K. Offill, M. Brown, S. Sebring, K. Collins, and J. Randolph for assistance in the field. Funding for this study was provided by the U.S. Army Corps of Engineers, Tulsa District.

10 LITERATURE CITED Bonner, T. H., and G. R. Wilde Changes in the Canadian River fish assemblage associated with reservoir construction. Journal of Freshwater Ecology 15: Bottrell, C. E., R. H. Ingersol, and R. W. Jones Notes on the embryology, early development, and behavior of Hybopsis aestivalis tetranemus (Gilbert). Transactions of the American Microscopical Society 83: Cross, F. B., O. T. Gorman, and S. G. Haslouer The Red River shiner, Notropis bairdi, in Kansas with notes on depletion of its Arkansas River cognate, Notropis girardi. Transactions of the Kansas Academy of Science 86: Cross, F. B., and R. E. Moss Historic changes in fish communities and aquatic habitats in plains streams of Kansas, pp In W. J. Matthews and D. C. Heins, editors. Community and evolutionary ecology of North American stream fishes. University of Oklahoma Press, Norman. Friedman. J. M., W. R. Osterkamp, M. L. Scott, and G. T. Auble Downstream effects of dams on channel geometry and bottomland vegetation: regional patterns in the Great Plains. Wetlands 18: Holden, P. B Ecology of riverine fishes in regulated stream systems with emphasis on the Colorado River, pp In J. V. Ward and J. A. Stanford, editors. The ecology of regulated streams. Plenum Press, New York. Larson, R. D., A. A. Echelle, and A. V. Zale Life history and distribution of the Arkansas River shiner in Oklahoma. Final Report Federal Aid Project E-8.

11 Oklahoma Department of Wildlife Conservation, Oklahoma City. Limbird, R. L The Arkansas River- a changing river. Pages 81-94, In L. W. Hesse, C. B. Stalnaker, N. B. Benson, and J. R. Zuboy, editors. Restoration planning for the rivers of the Mississippi River ecosystem. National Biological Survey. Washington, D.C. Luttrell, G. R., A. A. Echelle, W. L. Fisher, and D. J. Eisenhour Declining status of two species of the Macrohybopsis aestivalis complex (Teleostei: Cyprinidae) in the Arkansas River basin and related effects of reservoirs as barriers to dispersal. Copeia 1999: Matthews, W. J Physicochemical tolerance and selectivity of stream fishes as related to their geographic ranges and local distributions, pp In W. J. Matthews and D. C. Heins, editors. Community and evolutionary ecology of North American stream fishes. University of Oklahoma Press, Norman. Matthews, W. J. and L. G. Hill Influence of physicochemical factors in habitat selection by red shiners, Notropis lutrensis. Copeia 1979: Matthews, W. J. and L. G. Hill Habitat partitioning in the fish community of a southwestern river. Southwestern Naturalist 25: McCune, B., and M. J. Mefford Multivariate analysis of ecological data. MjM Software, Gleneden Beach, Oregon. Moore, G. A Notes on the early life history of Notropis girardi. Copeia 1944: Patton, T. M., and W. A. Hubert Reservoirs on a Great Plains stream

12 affect downstream habitat and fish assemblages. Journal of Freshwater Ecology 8: Pigg, J Decreasing distribution and current status of the Arkansas River shiner, Notropis girardi, in the rivers of Oklahoma and Kansas. Proceedings of the Oklahoma Academy of Science 71:5-15. Pigg, J., M. S. Coleman, and J. Duncan An ecological investigation of the ichthyofauna of the North Canadian River in Oklahoma: Proceedings of the Oklahoma Academy of Science 72: Pigg, J., R. Gibbs, and K. K. Cunningham Decreasing abundance of the Arkansas River shiner in the South Canadian River, Oklahoma. Proceedings of the Oklahoma Academy of Science 79:7-12. Pflieger, W. L., and T. B. Grace Changes in the fish fauna of the lower Missouri River, , pp In W. J. Matthews and D. C. Heins, editors. Community and evolutionary ecology of North American stream fishes. University of Oklahoma Press, Norman. Platania, S. P., and C. S. Altenbach Reproductive strategies and egg types of seven Rio Grande Basin cyprinids. Copeia 1998: Polivka, K. M The microhabitat distribution of the Arkansas River shiner, Notropis girardi: a habitat-mosaic approach. Environmental Biology of Fishes 55: Stinnett, D. P., R. W. Smith, and S. W. Conrady Riparian areas of western Oklahoma: a case study of the Canadian River. Pages 22-29, In P. J. Stuber, coordinator. Proceedings of the National Symposium on Protection of Wetlands from

13 Agricultural Impacts. U. S. Fish and Wildlife Service Biological Report 88(16). Washington, D.C. SAS Institute Inc SAS version 8.0. Cary, North Carolina. Sublette, J. E., M. D. Hatch, and M. Sublette The fishes of New Mexico. University of New Mexico, Albuquerque. Wilde, G. R., and T. H. Bonner First records of suckermouth minnow Phenacobius mirabilis from the Canadian River, Texas. Texas Journal of Science 52:71-74 Wilde, G. R., T. H. Bonner, and R. Patiño Habitat use and ecology of the Arkansas River shiner and speckled chub in the Canadian River, New Mexico and Texas. Final Report to the US Fish and Wildlife Service. Department of Range, Wildlife, and Fisheries Management, Texas Tech University, Lubbock. Williams, G. P., and M. G. Wolman Downstream effects of dams on alluvial rivers. U.S. Geological Survey Professional Paper Washington, D. C.

14 Table 1. Sites sampled on the North Canadian and Beaver rivers, Oklahoma, 5-7 July 2000 and August Habitat sampling was conducted at sites 1, 4, and 6. Site 1. North Canadian River at 6-mile road, Canton Lake recreation area, Dewey County, Oklahoma (5 July 2000, 10 August 2001). Site 2. North Canadian River at US Hwy 281, 2 mile N of Seling, Major County, Oklahoma (5 July 2000, 10 August 2001). Site 3. North Canadian River at EW54RD, 5 miles N and 7 miles W of Seling, Woodward County, Oklahoma (5 July 2000, 10 August 2001). Site 4. North Canadian River at State Hwy 50, 1 mile S and 8 miles E of Woodward, Woodward County, Oklahoma (5 July 2000, 10 August 2001). Site 5. Beaver River at US Hwy 183, 1 mile N and 1 mile W of Fort Supply, Woodward County, Oklahoma (6 July 2000, 11 August 2001). Site 6. Beaver River at State Hwy 149, 2.5 miles E of Laverne, Harper County, Oklahoma (6 July 2000, 11 August 2001). Site 7. Beaver River at NS165 Rd, 4 miles S of Gate, Beaver County, Oklahoma (6 July 2000, 11 August 2001). Site 8. Beaver River at US Hwy 270, 0.5 mile N of Beaver, Beaver County, Oklahoma (6 July 2000, 11 August 2001). Site 9. Beaver River at US Hwy 83, 4 miles S and 18 miles E of Beaver, Beaver County, Oklahoma (6 July 2000, 11 August 2001). Site 10. Beaver River, 500m downstream from Lake Optima, Texas County, Oklahoma (7 July 2000, 11 August 2001).

15 Table 2. Composition (%) of the fish assemblage of the North Canadian and Beaver rivers, Oklahoma, 5-7 July Site locations are given in Table 1. North Canadian River Beaver River Species Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8 Site 9 Site 10 Gizzard shad Dorosoma cepedianum Channel catfish Ictalurus punctatus Bullhead minnow Pimephales vigilax Common carp Cyprinus carpio Emerald shiner Notropis atherinoides 2.53 Fathead minnow Pimephales promelas Red shiner Cyprinella lutrensis Sand Shiner Notropis stramineus Suckermouth minnow Phenacobius mirabilis Plains killifish Fundulus zebrinus Inland silverside Menidia beryllina 1.27 Mosquitofish Gambusia affinis Bluegill Lepomis macrochirus Green sunfish Lepomis cyanellus 0.42 Longear sunfish Lepomis megalotis Largemouth bass Micropterus salmoides 5.32 White crappie Pomoxis annularis 1.92 Number of fish collected

16 Table 3. Composition (%) of the fish assemblage of the North Canadian and Beaver rivers, Oklahoma, August Site locations are given in Table 1. North Canadian River Beaver River Species Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8 Site 9 Site 10 Gizzard shad Dorosoma cepedianum Yellow bullhead Ameiurus natalis 0.10 Channel catfish Ictalurus punctatus Bullhead minnow Pimephales vigilax Common carp Cyprinus carpio Emerald shiner Notropis atherinoides 2.53 Fathead minnow Pimephales promelas Red shiner Cyprinella lutrensis Sand Shiner Notropis stramineus Suckermouth minnow Phenacobius mirabilis Smallmouth buffalo Ictiobus bubalus 0.22 Plains killifish Fundulus zebrinus Brook silverside Labidesthes sicculus 1.68 Inland silverside Menidia beryllina Mosquitofish Gambusia affinis Freshwater drum Aplodinotus grunniens Bluegill Lepomis macrochirus Green sunfish Lepomis cyanellus Longear sunfish Lepomis megalotis Largemouth bass Micropterus salmoides White crappie Pomoxis annularis 0.30 Striped bass Morone saxatilis Total fish collected

17 Table 4. Composition (%) of the fish assemblage of the North Canadian and Beaver rivers, Oklahoma, during summer and fall 2000 quarterly sampling. Site locations are given in Table 1. Species Site 1 North Canadian 6-mile Rd, Canton Lake Site 4 North Canadian State Hwy 50, E of Woodward Site 6 Beaver State Hwy 149, E of Laverne 14 August 13 October 14 August 13 October 14 August 13 October Gizzard shad Dorosoma cepedianum Channel catfish Ictalurus punctatus Bullhead minnow Pimephales vigilax Fathead minnow Pimephales promelas Red shiner Cyprinella lutrensis Sand shiner Notropis stramineus Suckermouth minnow Phenacobius mirabilis Plains killifish Fundulus zebrinus Inland silverside Menidia beryllina Mosquitofish Gambusia affinis Freshwater drum Aplodinotus grunniens Green sunfish Lepomis cyanellus 0.30 Total fish collected

18 Table 5. Composition (%) of the fish assemblage of the North Canadian and Beaver rivers, Oklahoma, during summer and fall 2001 quarterly sampling. Site locations are given in Table 1. Species Site 1 North Canadian 6-mile Rd, Canton Lake Site 4 North Canadian State Hwy 50, E of Woodward Site 6 Beaver State Hwy 149, E of Laverne 22 June 28 Sept. 22 June 28 Sept. 23 June 29 Sept. Gizzard shad Dorosoma cepedianum Channel catfish Ictalurus punctatus Blacktail shiner Cyprinella venusta 5.79 Bullhead minnow Pimephales vigilax 0.41 Common carp Cyprinus carpio 0.41 Fathead minnow Pimephales promelas Red shiner Cyprinella lutrensis Sand shiner Notropis stramineus Suckermouth minnow Phenacobius mirabilis River carpsucker Carpiodes carpio Smallmouth buffalo Ictiobus bubalus 0.83 Plains killifish Fundulus zebrinus Brook silverside Labidesthes sicculus 0.86 Inland silverside Menidia beryllina Mosquitofish Gambusia affinis Freshwater drum Aplodinotus grunniens 1.16 Green sunfish Lepomis cyanellus 1.16 Bluegill Lepomis macrochirus Longear sunfish Lepomis megalotis

19 Table 5. Concluded. Species Site 1 North Canadian 6-mile Rd, Canton Lake Site 4 North Canadian State Hwy 50, E of Woodward Site 6 Beaver State Hwy 149, E of Laverne 22 June 28 Sept. 22 June 28 Sept. 23 June 29 Sept. Largemouth bass Micropterus salmoides 0.39 Redear sunfish Lepomis microlophus 0.21 White bass Morone chrysops Bigscale logperch Percina macrolepida 0.83 Total fish collected

20 Table 6. Means (n = 50) for environmental variables on each sampling date. Site locations are given in Table 1. North Canadian River Site 1 North Canadian River Site 4 14/08/00 13/10/00 22/06/01 28/09/01 14/08/00 13/10/00 22/06/01 28/09/01 Current (m sec -1 ) Temperature ( O C) Dissolved oxygen (ppm) Conductivity (µs/cm) ph Turbidity (NTU) Depth (cm) Width (m) Discharge (m 3 sec -1 ) Shade (%) Cover (%) Sand (%) Silt (%) Gravel (%)

21 Table 6. Concluded. Beaver River Site 6 14/08/00 13/10/00 23/06/01 28/09/01 Current (m sec -1 ) Temperature ( O C) Dissolved oxygen (ppm) Conductivity (µs/cm) ph Turbidity (NTU) Depth (cm) Width (m) Discharge (m 3 sec -1 ) Shade (%) Cover (%) Sand (%) Silt (%) Gravel (%)

22 FIGURE LEGENDS Figure 1. Canonical correspondence ordination of samples from North Canadian River Site 1 (NC1), North Canadian River Site 4 (NC2), and Beaver River Site 6 (BR1). Numbers following hyphens (e.g., NC1-1, NC-2, NC-3, NC-4) referred to different sampling dates: 1 = 14 August 2000, 2 = 13 October 2000, 3 = 22 June 2001, and 4 = September Abreviations for species and environmental variables are: gshad = gizzard shad, vigilax = bullhead minnow, menidia= Mississippi silverside, red = red shiner, catfish -= channel catfish, bluegill = bluegill, mosquito = mosquitofish, suckermo = suckermouth minnow, sand = sand shiner (partially obscured by label BR1-4 in figure), killifish = plains killifish, fathead = fathead minnow, Width = stream width, Conducti = conductivity, Depth = stream depth, Shade = proportion of transect that was shaded, Current = current velocity, Turbit = turbidity, and Cover = proportion of the transect with in-stream cover. Figure 2. Comparison of available habitat, based on current velocity (top panel), and that used by Arkansas River shiner in the Canadian River (2 nd panel) based on results of Wilde et al. (2000). Panels 3-5, respectively, show available habitat, based on current velocity, in the North Canadian River at sites 1 and 4, and in the Beaver River at Site 6. Figure 2. Comparison of available habitat, based on water depth (top panel), and that used by Arkansas River shiner in the Canadian River (2 nd panel) based on results of Wilde et al. (2000). Panels 3-5, respectively, show available habitat, based on water depth, in the North Canadian River at sites 1 and 4, and in the Beaver River at Site 6.

23 North Canadian River NC1-4 NC2-2 NC1-1 NC2-4 bluegill NC2-1 red Shade catfish Turbidit Width Conducti mosquito Current Cover menidia Depth suckermo BR-1 2 A xi s sand BR-4 killifis BR-2 fathead BR-3 NC1-3 vigilax gshad NC1-2 NC2-3 Axis 1

24 Canadian River Availability (%) Canadian River New Mexico and Texas Habitat Selection in Canadian River (%) Arkansas River shiner habitat selection Habitat Availability (%) in the North Canadian River North Canadian River Site 1 North Canadian River Site 4 Beaver River Site Current Velocity (cm sec -1 )

25 Canadian River Availability (%) Canadian River New Mexico and Texas Habitat Selection in Canadian River (%) Arkansas River shiner habitat selection Habitat Availability (%) in the North Canadian River North Canadian River Site 1 North Canadian River Site 4 Beaver River Site Depth (cm)