Download or read book Biological Evaluation of Rotenone Treatment and First Year Fish Restocking Program on Sprague Lake, Adams County, Washington written by John T. Whalen and published by . This book was released on 1989 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: "On October 3 and 4,1985 the entire upper Cow Creek drainage, including Sprague Lake In Adams and Lincoln Counties, was treated with rotenone. The purpose of this treatment was to eliminate dominant populations of carp (Cyprlnus carpio Llnaeus), stunted yellow perch (Perea t!avescens Mitchell), brown bullhead (lctalurus nebulosus Lesueur), and other undesirable fish species. The fishery management goal for Sprague Lake was to establish, develop, and sustain a warm water sport fishery for largemouth bass (Micropterus salmoides Lacepede), smallmouth bass (Micropteros dolomieui Lacepede), bluegill (Lepomis macrochirus Rafinesque), and walleye (Stizostedion vitreum vitreum Mitchell). As an Interim fishery, rainbow trout (Oncorynchus mykiss Richardson) and Lahontan cutthroat trout (Oncorhynchus clarki henshawi Richardson) were stocked to supply an immediate fishery, whlle slower growing warm water fish species were becoming established. The purpose of this study was to determine how effective the Sprague Lake rotenone treatment, and post rehabilitation fish planting program, was in: 1) eliminating undesirable fish species and controlling their reestablishment; 2) establishing game fish populations In the lake following rotenone detoxification, with particular emphasis on warm water fish species establishment; and 3) promoting increased recreational fishing on a sustained basis. These objectives were addressed by conducting creel surveys, gill netting and electroflshing surveys, fish food habits analysis, and analyses of fish growth, benthic macroinvertebrate abundance, zooplankton abundance, phytoplankton biovolume, and water quality. Prior to the rotenone treatment, the Washington Department of Game (Washington Department of Wild!ife, as of 1986), estimated total angler pressure for the upper Cow Creek drainage to be approximately 1700 angler days of recreational fishing per year. Based on post rehabilitation creel survey data collected during 1986, fishing pressure on Sprague Lake alone was 19,954 angler days. Economic analysis of the 1986 sport fishery determined that the interim trout fishery generated $239,960 In economic value to the state of Washington. The trout fishery established in Sprague Lake during 1986 was clearly successful in terms of increasing recreational fishing usage of the lake, and providing direct and indirect economic benefits to the community of Sprague and the State of Washington. The potential exists for Sprague Lake to continue to provide recreational and economic benefits, particularly with a growing warm water sport fishery. Relative abundance surveys conducted following the October 1985 rotenone treatment, and during 1986, Indicated that carp, yellow perch pumpkinseed (Lepomis gibbosus Llnnaeus), black crappie (Pomoxis nigromaculatus Lesueur), and grass pickerel (Esox americanus Gmelin) were effectively eliminated from Sprague Lake. However, brown bullhead and tench (Tinea tinea Linnaeus) were collected in electrofishing and gilI net surveys during 1986. Comparisons of growth and condition values exhibited by the six game fish species stocked into Sprague Lake were compared with results from other Pacific Northwest and Washington State field studies. With the exception of age 0+ bluegill, essentially all of the species and age classes of warm water fish which were stocked Into Sprague Lake, or which produced young of the year in Sprague Lake during 1986, had average condition factor values which were either higher or essentially equal to reported average condition values. Age 1 + rainbow trout which were introduced Into Sprague Lake during 1986 had averaged condition factor values of 1.17. Age 1+ rainbow trout which weighted an averaged of 79.2 grams when planted in March of 1986, averaged 692.1 grams in October of 1986. In order to assess the availability of fish food resources, Sprague Lake zooplankton and benthic macroinvertebrate densities were evaluated. Comparable cladoceran density values for August, September, and October, of 1985 and 1986, showed a significant increase in density values for larger cladoceran species such as Daphnia leavis and Daphnia scholderi. The increase in density values for these larger cladocerans during 1986 may be attributable to the elimination of the large populations of yellow perch and carp. The rotenone treatment appeared to have little direct impact on benthic Invertebrate densities. The three major Diptera taxa, and the aquatic worms, identlfled from 1985 and 1986 benthic samples, may have benefited indirectly from the rotenone treatment. Comparable benthic invertebrate density values for September of 1985 and 1986, for all benthic taxa identifled, showed signiflcant increases in lake wide density values between 1985 and 1986. Average lake-wide density values for Chaoborinae and Tanypodinae increased from 0.00 to 10.42 organisms per square meter. Density values for Chironominae increased from 28 to 817 organisms per square meter. Oligochaeta denslty values increased from 364 to 1041 organisms per square meter. The primary effects of the restoration on water quality were on phosphorus levels and phytoplankton biovolume. Calculated average values for orthophosphate phosphorus reported by Dlon et al (1980), for August and September of 1975, were 0.03 ± 0.06 mg/l, and 0.004 ± 0.001 mg/l, respectively. Orthophosphate values for Sprague lake during September of 1985 averaged 0.031 ± 0.008 mg/l. Average orthophosphate values for August and September of 1986 were 0.05 ± 0.01 and 0.09 ± 0.00 mg/1, respectively. In response to increased nutrients (primarily orthophosphate phosphorus), phytoplankton biovolume averages increased during 1986. Total phytoplankton blovolume, for August, September, and November of 1985 and 1986, averaged 3.558 mm3/mI during 1985, and 43.114 mm3/mI during 1986. Diet analysis indicated that all age classes of trout, and the young of the year and yearling age classes of warm water fish species, utilized common prey items. Cladocera, Diptera larvae, Diptera pupae, and Amphipoda were the four prey categories utilized most frequently by the nine species of fish studied. Significant diet overlaps were identified within and between nearly all species.utilizing these prey categories. The utilization of similar prey items by the various fish speciesand age classes of fish within Sprague Lake, raises the potential for intensified competition if food resources become limited. Sprague Lake's ability to ultimately support a productive, and economically feasible, mixed species fishery, may hinge on how successful warm water fish species reproduction efforts are, within two to five years following initial lake restocking efforts. Successful warm water species reproduction, on an annual basis, would insure a renewable supply of forage fish, reduce the potential for dominant year classes within forage and Piscivorus fish populations, and reduce predation pressures on planted fingerling salmonids. The potential economic benefits of fisheries Programs based on intentional mixed species fish management could be considerable, in terms of fish stocking costs, lake rehabilitation costs, and increased year-around fishing utiIization"--Document.