Fishes of Oklahoma Springs

-NO comprehensive evaluation exists for the fish fauna of springs in Oklahoma. In summers of 1981 and 1982, we documented the fish fauna of 50 springs located in aquifers throughout Oklahoma. Fishes were found in 19 of the 50 springs, with a total of 24 species represented. The fish fauna was richest in springs with substantial flow and bottoms clear of detritus, leaf litter, or mud, characteristic of uplands in northeast and southcentral Oklahoma. Multivariate analyses indicated the importance of substantial discharge in fish faunal richness, and that the richest fish faunas were in springs with a tendency toward the following combined characteristics: cool temperatures, gravel or sand bottoms, wide headpools or runs, high alkalinity, and high pH. Degradation of spring environments is obvious in many areas, and protection of the springs from further cultural alteration should be of primary concern. Springs are unique aquatic environments, often providing habitat for taxonomically or ecologically interesting organisms. Some widespread fishes in the United States are found almost exclusively in springs or spring-fed environments. Many springs in southern or western states harbor endemic fish species, including several federally considered threatened or endangered (Federal Register, 1975). Despite the advanced state of ichthyological investigation in most of North America, new species of fish continue to be found in isolated spring localities (Williams and Etnier, 1982). Natural springs are numerous and widespread in Oklahoma. At least 116 named and 149 unnamed springs are identified on USGS topographic maps of the State (Margaret Cibis, Oklahoma Geological Survey, personal communication), and the present survey revealed numerous springs not on USGS maps. Fishes from springs of Oklahoma have been collected only incidentally in various faunal surveys (Hubbs and Ortenburger, 1929; Blair, 1959; Moore, 1972). Many springs in the state, however, have not been visited previously by ichthyologists, and until now there has been no study to evaluate spring fish faunas throughout Oklahoma. During the last century withdrawal of ground water has resulted in lowered water tables and resultant declining flow or destruction of springs in Oklahoma and neighboring states (Brune, 1975). Additionally, many springs have been culturally altered, e.g., by concrete or stone modification of the head pool, to enhance their use for water supply. In light of declining quality of natural spring environments in the Southwest, the unique nature of spring faunas, and lack of information on Oklahoma spring faunas, we surveyed fishes and invertebrates of 50 springs throughout Oklahoma (Fig. 1). This paper describes the spring fish fauna, and relationships between fish occurrence and physical characteristics of the springs. METHODS. -Owners of more than 100 springs shown on USGS 7.5 or 15 minute topographic maps of Oklahoma were contacted. On the basis of landowner descriptions or information on alternate sites, we studied 50 springs throughout the state (Appendix A; Fig. 1) that appeared likely to have permanent populations of aquatic organisms. All 50 springs were sampled in MayTHE SOUTHWESTERN NATURALIST 30(1):23-32 MARCH 27, 1985 This content downloaded from 157.55. 39.80 on Fri, 22 Apr 2016 05:19:51 UTC All use subject to http://about.jstor. org/terms The Southwestern Naturalist FIG. 1. -Locations of springs sampled in this study. Numbers correspond to spring numbers in Table 1. August 1981, and 49 of the springs were sampled in June-July 1982, on as nearly the same calendar dates as possible in both years. Fishes were collected with a 4.5 m x 4.8 mm mesh seine in the head pool (if one existed) and in the spring run for a distance not exceeding 100 m. Supplementary documentation of species was by dip netting and visual observation. Collecting continued until no additional species were taken. Voucher specimens are in the Stovall Museum of Science and History, University of Oklahoma. Because of the potentially fragile nature of spring fauna, large series of fish were not preserved, and all but voucher specimens were released. Physical dimensions of all springs were measured; discharge was calculated from flow measurements taken with a floating object at the outflow of the head pool if one existed, or in the run if there was no actual head pool. Alkalinity, pH, conductivity, and oxygen were measured. Percent substrate composed of various sized particles or covered by leaf litter and detritus was estimated visually. Levins' (1968) index (= 1/ Pi2) was used to calculate substrate complexity, based on the proportion (pi) of each substrate type in the spring. Each spring was mapped and a detailed description was made of the physical setting, including any cultural modifications. Multivariate analyses of physical characteristics of springs (data standardized so that mean = 0 and standard deviation = 1.0) were done with NTY-SYS programs developed by F. J. Rohlf, J. Kispaugh, and R. Bartcher. UPGMA cluster analysis of the correlation matrix from physical variables was used to produce a dendrogram of similarity of the 50 springs. Principal components analysis was used to provide ordination of springs on the basis of the physical variables. Results of both analyses provide complimentary information and are presented as recommended by Sneath and Sokal (1973). RESULTS. -Springs of substantial size were found throughout Oklahoma, ranging from class 3 to class 8, following Meinzer (1927). Those with greatest discharge were in the Ozark uplift of northeastern Oklahoma, and the Arbuckle uplift in the southcentral part of the state (Fig. 1). Major cultural alteration, e.g., damming or addition of rock or concrete walls to natural channels, was found in 21 of the 50 springs, and only 22 lacked any evidence of man-made modifications. Such alterations were not necessarily detrimental to the existence of fishes, as fish were taken in 7 springs considered to have major cultural modifications. Such modifications may, however, have changed the original fish faunas to an unknown degree. Fish were found in 19 of the 50 springs (Table 1). Of the 24 species collected in springs the taxa occurring most often were Gambusia affinis, Lepomis cyanellus, Campostoma anomalum, Phoxinus erythrogaster, and Etheostoma spectabile (Table 1). Lepomis cyanellus was the most widely distributed, occurring in clear, rocky or gravel-bottomed springs in the Ozark, Ouachita, and Arbuckle uplifts, and in muddy or sandy springs in 24 vol. 30, no. 1 This content downloaded from 157.55. 39.80 on Fri, 22 Apr 2016 05:19:51 UTC All use subject to http://about.jstor. org/terms TABLE I. -Occurrence of fish in springs of Oklahoma 1981 and 1982, X = collected in only one year; XX = collected in both years. SPRING NUMBER Number of Springs Species 1 2 6 7 8 12 16 17 19 21 22 23 33 35 37 38 44 46 49 Occupied Campostoma anomalum Notemigonus crysoleucas Notropis lutrensis Notropis pilsbryi Notropis stramineus Phoxinus erythrogaster Pimephales promelas Semotilus atromaculatus Ictalurus melas IctcAlurus natalis Gambusia affinis I abidesthes sicculus Fundulus notatus Fundulus zebrinas Lepomis cyanellus Lepomis humilis Lepomis macrochirus Lepomis megalotis L. cyanellus x macrochirus Micropterus salmoides Etheostoma cragini Etheostoma microperca Etheostoma radiosum Etheostoma spectabile Cottus carolinae X XX XX X X X XX 7