O. Eugene Maughan

Ultrasonic Telemetry Technique for Monitoring Bluegill Movement

Abstract Ultrasonic transmitters were implanted in the peritoneal cavity of male bluegills (Lepomis macrochirus) 195 mm long or longer to monitor movements in a large reservoir. Surgical procedures were evaluated and new reception and transmission techniques were developed without prohibitively increasing transmitter size. A preamplifier and filter were developed that extended the maximum signal detection range to 400 m, and transmission frequency was lowered to extend the maximum operating life of the transmitter from less than 1 day to 30 days.

Community Structure and Seasonal Changes in Standing Stocks of Fish in a Warm-water Stream

A comprehensive study of the standing stocks of fish species in Glover Creek, Oklahoma, was conducted on a seasonal basis from 1977-1979. Community structure was described by biomass of species and feeding guilds and comparisons were made among seasons. Invertivore and invertivore-piscivore feeding guilds contained 79.9%o of the total fish standing stock. Guild structure differed among riffles and pools and varied less seasonally than between habitat types. The annual average total fish standing stocks were 60 and 90 kg/ha, for riffle and pool sites, respectively. Total standing stocks differed among seasons with the annual average occurring in April-May and October-November, and the maximum occurring during July-August. INTRODUCTION More reliable assessments of habitat impacts on streams could be made using a biological integrity approach rather than indicator species or diversity approaches (Cairns, 1977; Karr, 1981). Karr (1981) recently proposed a method to assess the biological integrity of stream fish communities. However, one of the basic assumptions of Karrs method is that biologists know what the structure of the fish community should be in unmodified habitats, and can then compare the observed community attributes with those expected under unmodified conditions. Although many studies have investigated how fish species richness varies with stream order (Huet, 1959; Sheldon, 1968), flow variability (Horwitz, 1978) and habitat structure (Gorman and Karr, 1978), relatively few investigators have attempted to quantify community trophic structure and seasonal changes in fish biomass in unmodified stream systems. For example, Funk (1975) found only seven studies of streams inhabited by black bass (Micropterus), in which composition of total fish biomass was estimated. Most of the studies reviewed by Funk (1975) suffered from four limitations: (1) smaller fish species were not considered; (2) estimates of total fish biomass were conducted only in pools; (3) population estimates were taken during one season giving no indication of typical seasonal variation, and (4) interpretation was complicated by the large number of species, even when smaller fishes were excluded. Schlosser (1982a) found that trophic structure was stable across both seasons and years in an unmodified stream, yet was seasonally unstable in a modified stream. Furthermore, Schlosser (1982b) attributed spatial variation in community organization to habitat structure and the temporal variability in habitat and food availability. However, few comparable studies assess the generality of Schlossers findings. The objective of this study was to describe the structure of the fish community in an unmodified stream in relation to season and habitat type. Specifically, we ask: (1) Do fish communities in unmodified streams have a stable trophic structure? (2) Are there general differences in trophic structure between riffle and pool habitats? and (3) Does a typical seasonal pattern in total fish biomass exist? STUDY AREA The study area was located on Glover Creek in SE Oklahoma (Orth and Maughan, I Present address: Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 2 Cooperators are the Oklahoma Department of Wildlife Conservation, Oklahoma State University, and the U.S. Fish and Wildlife Service.

Generalized Model for Predicting Spawning Success of Fish in Reservoirs with Fluctuating Water Levels

Abstract A computer model (SUCCESS) was developed to predict spawning success of centrarchid fishes in a pumped storage reservoir. The model was quantified by conducting field and laboratory studies with bluegills (Lepomis macrochirus) from Leesville Lake, the lower impoundment of the Smith Mountain Pumped Storage Project near Roanoke, Virginia. Eight modifiable subprograms were used to increase the generality and utility of the model. Data necessary for use in the model are hourly water levels, water temperature regimens, and a distribution describing the depth of spawning activity in the reservoir. A sensitivity analysis of the model suggested that data on hatchability and rates of hatching and development from the fry to free-swimming stage had the greatest effect on the estimates of spawning success. SUCCESS should allow a reservoir fishery manager to predict the impact of water level fluctuations on spawning success of sport fishes or predict spawning success of undesirable species under various wate...

Accurate and efficient estimation of benthic populations: A comparison between removal estimation and conventional sampling techniques

A Circular Depletion Sampler (CDS) was designed to allow the removal of consecutive subsamples from a sample area, while minimizing immigration and emigration. Equal sampling effort was expended during each removal period to permit estimation of both the probability of capture, and the number of individuals not captured from a sample area. Average probabilities of capture from 270 CDS samples ranged from 0.19 per minute for Antocha (Tipulidae) to 0.96 for Paratendipes (Chiroal (3 removal periods), Surber, and kick-net methods. Removal population estimates were consistently higher and less variable than those of the other methods. Estimates of diversity from samples taken with conventional methods were biased by differences in catchability, and by emigration. Separation of benthos from detritus took about twice as long per unit sample area for Surber and kick-net methods, although sampling time per unit area was nearly equal for all three methods. Removal estimates using only the first two catches were comparable to estimates based on three catches, indicating a further possible increase in efficiency.

Habitat Use of Two Darter Species in Glover River, Oklahoma

Channel darters have generally been reported to inhabit areas of moderate current over bedrock substrate (Cross, 1967), gravelly sections of slow-flowing streams (Miller, 1973; Miller and Robison, 1973), and deeper water in larger streams (Blair, 1959). Logperch have been reported to prefer clear streams with gravel and rocky bottoms and to be found in deep water in or at the base of riffles near pools (Lachner et al., 1950; Thomas, 1970). Generally these species occupy permanently flowing streams. They are, however, resident in Glover River which in the summer is often reduced to isolated pools kept fresh by subsurface flow (Orth and Maughan, 1982). It was hypothesized that habitat use in this stream might differ from use in more typical habitats occupied by this species. Darters were collected by electroshocking quarterly from 1978 to 1980 at 14 sites of known area (Jones et al., 1984) along the Glover River. Measurements were made on depth, velocity and substrate at each individual capture location and on habitat measurements along several transects at each site once each quarter, using techniques outlined by Orth and Maughan (1982). Frequencies were divided in each interval of water depth, water velocity, and substrate type by available area within each respective interval to obtain an estimate of relative density. Logperch were captured most frequently in pools, although they were occasionally taken in deeper riffles and runs in spring. Captures were made

Changes in Fish Stocks After Major Fish Kills in the Clinch River near St. Paul, Virginia

Fish populations were sampled during 1973 and 1974 in a section of the Clinch River, near St. Paul, Virginia, that was subjected to chemically induced fish kills in 1967 and 1970. Species composition and relative abundance were compared with those from prekill, postkill and postkill recovery periods. A slight decrease in number of species and a change in relative abundance were found. Our data support the findings of others that general recovery following fish kills is relatively rapid. (auth)