A survey of the fishes in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 by Steven P. Platania and Kevin R. Bestgen 2808 Morningside Drive Albuquerque, NM 87110 A report submitted to Department of the-Army Albuquerque District, Corps of Engineers P.O. Box 1580, 517 Gold Avenue, S.W. Albuquerque, NM 87103-1580 Purchase Order DACW47-88-M-0375 16 September 1988 000061 TABLE OF CONTENTS PAGE INTRODUCTION 1 STUDY AREA 3 METHODS 3 RESULTS 7 DISCUSSION 12 ACKNOWLEDGEMENTS 13 LITERATURE CITED 14 APPENDIX I 16 APPENDIX II 18 000062 LIST OF TABLES TABLE PAGE 1 Physico-chemical characteristics of collection localities in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 6 2 Scientific and common names of fish collected in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 8 Species occurrence and abundance in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 1 0 4 Species composition of collections made an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 11 000063 LIST OF FIGURES FIGURE PAGE 1 Collection localities in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 4 ZZZ 000064 INTRODUCTION The Rio Grande is the fifth longest river in North America. From its headwaters in the San Juan Mountains in southeastern Colorado, it flows approximately 2900 km south through New Mexico and then southeast near the Texas-New Mexico border. From there it forms the international boundary between the United States and Mexico before emptying into the Gulf of Mexico. Smith and Miller (1986) considered 154 species in 54 families as native to the Rio Grande basin. In New Mexico, the historic native ichthyofauna of the Rio Grande is thought to have consisted of at least 18 species (Smith and Miller 1986; Hatch 1985). Phantom shiner (Notropis orca), bluntnose shiner (Notropis sinus), and Rio Grande silvery minnow (Hybognathus amarus - formerly Hybognathus nuchalis), are endemic to the basin and are accorded endangered status (Group 1) by the state of New Mexico (New Mexico Department of Game and Fish 1985). The Rio Grande bluntnose shiner, (Notropis simus), was known from the lower reaches of the Rio Chama near Abiquiu, New Mexico, south to El Paso, Texas/Ciudad Juarez, Mexico (Chernoff et al. 1982). It was last collected in 1964 (a single specimen) near Pena Blanca, New Mexico (Fish Database, N.M. Dept. of Game and Fish). 000065 The phantom shiner occurred sporadically in the Rio Grande from the vicinity of Isleta, New Mexico downstream to El Paso, Texas and from the confluence of the Rio Grande and Pecos River downstream to near Brownsville, Texas. No individuals are known from the study area treated in this report. The last known specimen ,was collected in 1975 in the Rio Grande at Ciudad Diaz Ordaz, Tamaulipas, Mexico (Cheilloff et al. 1982). Chernoff et al. (1982) reviewed the taxonomy and status of Rio Grande bluntnose and phantom shiners and presumed that both may be extinct. The Rio Grande silvery minnow, Hyboonathus amarus, was formerly widespread in warmwater reaches of the Rio Grande basin. It was historically abundant in the Pecos River, New Mexico, and occurred in the Rio Grande in Texas downstream of Big Bend (Hubbs et al. 1977) to the Gulf of Mexico (Robinson 1959), but it is apparently extirpated from these regions. In the Rio Grande in New Mexico, it occurred from the lower portion of the Rio Chama downstream to the New Mexico-Texas border. It now persists in the middle Rio Grande downstream of Cochiti Reservoir to Elephant Butte Reservoir and is most common downstream of Albuquerque. The purpose of this survey was to determine whether Notropis simus simus and Hyboanathus amarus occurred in the study area and to assess the possible impacts of proposed wetland draining on these species. 2 000066 STUDY AREA An 8 km reach of the Rio Grande between Cochiti Dam and 1.75 km north of the Santo Domingo Pueblo Bridge (Site 13) was sampled on 19-20 July 1988. The Santa Fe River, the only natural tributary of the Rio Grande, in this area, was also sampled. Discharge of the Rio Grande in the study area is almost entirely controlled by Cochiti Dam. During this survey, discharge from Cochiti Dam ranged from 6.4 - 8.2 m 3/s (224 - 286 cf/s) on 19 July and increased from 8.2 - 10.8 m 3/s (286 - 380 cf/s) on 20 July. The river was primarily confined to a single channel with a substrate of cobble and rubble. Low water levels dried most secondary channels and reduced the amount of available backwater habitat. Additional sources of water include the Santa Fe River and return irrigation water. The Santa Fe River is a small stream which is impounded by Cochiti Dam. Below the dam, the river is recharged by springs and reservoir seep where it forms a wide, shallow, silt-mud settling basin. Water from this basin is directed through a narrow culvert and reforms the Santa Fe River which is about 2-3 m wide with an average depth less than 0.5 m. METHODS Fish were collected with a small mesh seine at 13 locations in the Rio Grande, Santa Fe River, and irrigation canals on 19 and 20 July 1988 (Figure 1). Nine collections were made in the 3 000067 COCHITI DAM Pena Blanca ■ South Boundary of the Pueblo de Cochiti Reservation Site ■ Pueblo de Santo Domingo Reservation 1 km 1 mile Figure 1. Collection localities in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988. 4 000068 Rio Grande, three in the Santa Fe River, and one in an irrigation canal. All of the collection localities, except Site 13, were on the Pueblo de Cochiti Reservation, Sandoval County, New Mexico. Site length varied from 50-300 m and all microhabitat types including oxbows, cut-off side channels, pools, riffles, runs, and backwaters were sampled. Downstream, upstream, and across- stream seining was employed and bank and instream cover and substrate were severely agitated. Several sites designated as "possible sample sites" on the Cochiti Pueblo base map supplied by the U.S. Army Corps of Engineers (USACE) were examined and found to be dry. Site 13 (approximately 2 km downstream of site 12) is located in Santo Domingo Pueblo. Small specimens were fixed in 10% formalin immediately after capture. Most fish > 250-mm standard length (SL) were identified, enumerated and released. Notes on habitat and species associations were made along with an approximation of site length, width, and maximum depth (Appendix I). Water temperature, dissolved oxygen, conductivity and salinity were measured and recorded (Table 1). All specimens were sorted, identified, enumerated, and catalogued into the fish range of the Museum of Southwestern Biology, Department of Biology, at the University of New Mexico. A list of specific site locations, field number, species, and number of specimens collected is appended (Appendix II). 5 000069 Table 1. Physico-chemical characteristics of collection localities in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988. SITE NUMBER TEMPERATURE DISSOLVED CONDUCTIVITY SALINITY (°C) OXYGEN (mg/1) (micromhos) (ppt) 1 22.3 16.8 390 0 2 21.2 12.2 400 0 3 25.0 14.2 400 4 21.6 12.6 390 0 5 18.3 12.6 440 0 6 24.6 13.2 500 0 7 20.2 12.3 480 0 8 21.1 11.8 395 0 9 21.3 11.5 380 10 22.2 11.9 400 0 11 22.8 12.8 410 0 12 23.1 12.1 410 0 13 no physico-chemical data taken at this site 6 000070 RESULTS Eighteen species of fish representing six orders and eight families were taken in the 13 collections made during this survey (Table 2). While no Notropis simus simus were collected, a total of 20 Hybognathus amarus were taken at two locations (Sites 3 and 13). Nine of the 18 species collected were native to the upper Rio Grande, New Mexico, and nine were introduced (Table 2). The most abundant species was the non-native Catostomus commersoni. It-was taken at all 13 stations and represented 77.6% of the total catch (Table 3). The second most abundant species was the native Pantosteus plebeius which, while also present at all 13 sites, only accounted for 7.9% of the catch (Table 3). Rhinichthys cataractae (7,5%), Gambusia affinis (3.8%), and Pimephales promelas (0.7%) were the next most common fishes. These five most abundant species represented almost 98% of the catch; the four native species in this group accounted for only 19%. Hybognathus amarus was taken at Sites 3 and 13 (Table 4). The first site was a side channel with reduced flow and a cobble- rubble substrate. Seventeen specimens were taken near the head of the side channel in the pool formed by the confluence of the main and side channels. The other three specimens were taken in a narrow (2 m), shallow (0.25 m), irrigation canal on Santo Domingo Pueblo (Site 13). 7 000071 Table 2. Scientific and common names of fish collected in an 8 km reach of the Rio Grande drainage below Cochiti Dam, July 1988 SCIENTIFIC NAME COMMON NAME Order Salmoniformes Family Salmonidae trouts Salmo olairdneri rainbow trout Salmo trutta brown trout Order Clupeiformes Family Clupeidae herrings I Dorosoma cepedianum gizzard shad Order Cypriniformes Family Cyprinidae carps and minnows I Cyprinus carpio common carp N Hybognathus amarus Rio Grande silvery minnow N Hybopsis qracilis flathead chub N Notropis lutrensis red shiner N Pimephales promelas fathead minnow N Rhinichthys cataractae longnose dace Family Catostomidae suckers N Carpiodes carpio river carpsucker I Catostomus commersoni white sucker N Pantosteus plebeius Rio Grande sucker Order Siluriformes Family Ictaluridae bullhead catfish Ictalurus melas black bullhead Order Atheriniformes Family Poeciliidae livebearers N -Gambusia affinis mosquitofish 8 000072 Table 2.