THE NATIVE FISH FAUNA OF MAJOR DRAINAGES EAST OF THE CONTINENTAL DIVIDE IN NEW MEXICO A Thesis Presented to the Graduate Faculty of Biology Eastern New Mexico University In Partial Fulfillment of the Requirements fdr -the7Degree: Master of Science in Biology by Michael D. Hatch December 1984 TABLE OF CONTENTS Page Introduction Study Area Procedures Results and Discussion Summary Acknowledgements Literature Cited Appendices Abstract INTRODUCTION r (t. The earliest impression of New Mexico's native fish fauna =Ems during the 1850's from naturalists attached to various government survey parties. Without the collections from these and other early surveys, the record of the native fish fauna would be severely deficient because, since that time, some 1 4 native species - or subspecies of fish have become extirpated and the ranges of an additionial 22 native species or subspecies have become severly re- stricted. Since the late Miocene, physiographical changes of drainages have linked New Mexico, to varying degrees, with contemporary ichthyofaunal elements or their progenitors from the Rocky Mountains, the Great Plains, the Chihuahuan Desert, the Mexican Plateau, the Sonoran Desert and the Great Basin. Immigra- tion from these areas contributed to the diversity of the state's native ichthyofauna. Over the millinea, the fate of these fishes waxed and waned in ell 4, response to the changing physical and _chenaca-l-conditions of the surrounding environment. Ultimately, one of the most diverse fish faunas of any of the interior southwestern states developed. Fourteen families comprising 67 species of fish are believed to have occupied New Mexico's waters historically, with strikingly different faunas evolving east and west of the Continental Divide. The fluvial systems that drain the west slope of the Continental Divide in New Mexico are tributaries of the Colorado River. The origin and composi- tion8of the native ichthyofauna in these drainages has received much attention (Miller 1958, Rinne 1969, Holden 1970, Smith et al. 1983, Minckley et al. in press). In contrast, only partial coverage has ever been attained of the origin and composition of the state's native ichthyofauna east of the Continental Divide. The aims of this paper are to: (1) present a summary and synthesis of 2c. historical information concerning the distribution of fishes east of the Continental Divide in New Mexico, (2) determine the major prehistoric events and conditions that governed the origin of the native fish fauna in these drainages, and (3) reconstruct this fauna as it likely existed at the start of the historic era (circa 1550 AD). STUDY AREA Rio Grande Basin - The Rio Grande originates in the San Juan Mountains of southwestern Colorado and flows in a southernly direction through New Mexico and along the border between Texas and Mexico for 1887 miles to the Gulf of Mexico. The river flows through a deeply incised (approximately 1,000 feet deep) and narrow canyon (ex. the flood plain is typically no wider than 50 feet) of the Taos Plateau as it enters New Mexico. The river exit.;- this canyon at Embudo, New Mexico and continues south through a broad valley that extends to Otowi bridge (just south of Santa Clara Pueblo), then becomes abruptly constricted as it enters another canyon that extends downstream to Cochiti Pueblo. For the remainder of its course in New Mexico, the Rio Grande flows through a broad valley of low relief. Stream gradients of 25 feet per mile are common upstream of Cochiti Pueblo; stream gradients of 5 feet per mile prevail between Cochiti Pueblo and El Paso. The Rio Grande upstream of Cochiti Pueblo is a perennial river with numerous perennial tributaries. Contrasting this, there are no perennial tributaries of the Rio Grande in New Mexico downstream of Cochiti Pueblo and much of this portion of the river is dewater6a—by, or as a result of, nthropogenic events for extensive periodl. However, this situation is not natural. Prior to settlement of the Rio Grande Valley by Anglo- Europeans, the Rio Grande was perennial throughout its course in New Mexico. Even the most arid part of the flood plain was characterized by numerous marshes, oxbow pools and a fringe-forest of cottonwoods, willows and shrubby phreatophytes. (Metcalf 1967). Miller (1961) cites the occurrance of Scaphirhynchus platorynchus taken near Albuquerque in 1873 and the ideff44-44-c4=-- --1:12MPTrf remains of Cycleptus eloncatus from an Indian site west of Santa Fe as evidence that the upper Rio Grande was once a larger river of more reliable flow. After the Civil Vi6r, western migration of Anglo-European settlls was accelerated and a large number of people settled in the state, especially in the Rio Grande Valley. As the population increased, the grazing industry emerged and irrigation activities intensified. By 1880, nearly all land in the Rio Grande Valley that could be irrigated was under development and people there had begun to complain of water shortages (Sorensen and Linford 1 970). By the end of the 19th century, grasslands were severely over grazed, and as a result, stream flows became more erratic, soil erosion was accelerated and the morphologhy of stream channels became wider and shallower. Lee (1907) described the Rio Grande north of El Paso as "mainly a flood-water stream subject to great fluctuations in volume". Beginning in 1914, vand generally more recently numerous large dams have ) been constructed in New Mexico on the Rio Grande and its major tributaries in an effort to alleviate water shortages and to control flooding. These include, Cabillo, Elephant Butte, Jemez, Cochiti, Gallisteo, McClure, Abiquiu, El Vado, and Heron. In addition, numerous smaller dams and irrigation diversions have been constructed in the Rio Grande basin in New Mexico. Water releases from these reservoirs fluctuate severely and downstream flows are often critically depleted. Membres Drainage - The Mimbres River drainage is an isolated fluvial system of the endorheic Guzman Basin. Perennial flowing water of the Mimbres River exists in two discrete segments. These segments are separated by a 11 km portion of the riverbed that is normally dry. One segment comprises the headwaters of the drainage, including the forks of the Mimbres River which originate on the western slope of the Black 10" Range of southwestern New Mexico. These forks merge within 5.0 - 6.5 of their origins to-form the main stem of the Mimbres River. The river con- tinues in a southerly direction for approximately 5 km at which point the water becomes subterranean. Within this segment, the Mimbres River is characterized as a high-gradient coldwater stream with moderate flows, alternating between riffle and shallow pool habitats. The downstream 6MA,A4 perennial segment of the Mimbres river extends approximately 40 km and -6.444-s as surface entity (except during flooding and high runoff) near Dwyer. This portion of the Mimbres River is characterized as a moderate gradient stream that flows within a well defined channel with numerous riffles and pools. Hower (1857) described the terminus of the Mimbres River in the 1850's as being a series of pools or lagoons, surrounded by thickets of willows (Salix spp.) for 4 to 6 miles above this point the river is said to have been up to 2.5 feet deep and to have flowed at 2.5 miles per hour, in the summer. Beginning in the late 1800's, the river has become wider and shallower--probably largely as a result of overgrazing (Boles and Dick-Peddie 1983). Today, the river terminus is usually dry, and ordinarily at high water the stream averages 13 feet wide and less than a foot in depth. Diversions have reduced the quantity of water in the river, while uneven flows, flooding, and repeated stream modifications by local landowners have combined to eliminate the conditions described by Antisell (op. cit.) to a drastic degree. Pecos Drainage - The Pecos River originates in the Sangre de Cristo Mountains of northern New Mexico and extends 920 km SSE to its confluence with the Rio Grande in west central Texas. Within New Mexico, the Pecos River is bounded on the east by the Llano Estacado, and on the west by a series of mountain ranges, including: the Gallinas, Jicarilla, Capitan, Sacramento and Guadalupe mountains. The Pecos River upstream from Pecos is a high-gradient, coldwater stream with swift, turbulent flows. Between Pecos and Lake Sumner, the river flows through •a region of rough topography where the river is entrenched and the gradient produces moderate to swift stream flows with numerous riffle areas. Between Lake Sumner and Lake McMillan, the river meanders. through a broad valley of low relief. The river between Lake McMillan and the state line flows through an area of low relief with a "stairstep" stream morphology. Here, stream flows alternate between riffle areas and deep pools. Much of the water in this section, and for some distance downstream in Texas, is brackish, with salinities as high as 25.1 ppt and frequently averaging greater than 10 ppt (Hubbs 1957, Hubbs and Echelle 1972). Four major reservoirs presently impound water of the Pecos River in New Mexico (i.e., Santa Rosa, Sumner, McMillan and Avalon dams). In addition Red Bluff Dam (in Texas) impounds water of the Pecos River that backs up into New Mexico, and there are several minor unpoundments in the Carlsbad area. The first of these impoundments (i.e., McMillan Reservoir) was con- structed in 1893. The timing and volume of water releases from these impoundments are dictated primarily by irrigation demands. During the irrigation season (April-October), releases from these impoundments fluctuate severely and downstream flows are often critically depleted, including by main channel diversions and pumping of ground and surface water.