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Articles 61 - 72 of 72
Full-Text Articles in Life Sciences
Trophic Interactions Between Fish And Invertebrates In Bear Lake, Utah-Idaho, Wayne A. Wurtsbaugh, Charles P. Hawkins
Trophic Interactions Between Fish And Invertebrates In Bear Lake, Utah-Idaho, Wayne A. Wurtsbaugh, Charles P. Hawkins
Watershed Sciences Faculty Publications
An intensive study of the limnology, invertebrates and fishes of Bear Lake was conducted in 1987 in order to define the productivity and food web of the community. Limno10gica1 parameters and invertebrates were measured at approximately monthly intervals while fish distribution and feeding was analyzed in February, June, August, and October. Samples were collected at three to eight stations along a transect running from the shallow littoral area on the west side of the lake, to the deep profundal zone.
Survival Of Trout Strains As Affected By Limnological Parameters, Wayne A. Wurtsbaugh
Survival Of Trout Strains As Affected By Limnological Parameters, Wayne A. Wurtsbaugh
Watershed Sciences Faculty Publications
Prior work at East Canyon Reservoir, Utah indicated that adult trout are important predators of stocked juvenile rainbow trout. Brown trout, in particular, were exclusively piscivorous when th~y exceeded 185 mm standard length. Fish became increasingly important in the diet of cutthroat trout greater than 330 mm. The purpose of this study was to further document the effect of adult trout on survival of juvenile rainbow trout in mid-elevation reservoirs. Causey Reservoir was chosen because it was thought to contain large brown and cutthroat trout and had not been intensively studied during the last eight years.
A Mass Mortality Of Fishes In Lake Titicaca (Peru-Bolivia) Associated With The Protozoan Parasite Ichthyophthirius Multifiliis, Wayne A. Wurtsbaugh, R. Alfaro
A Mass Mortality Of Fishes In Lake Titicaca (Peru-Bolivia) Associated With The Protozoan Parasite Ichthyophthirius Multifiliis, Wayne A. Wurtsbaugh, R. Alfaro
Watershed Sciences Faculty Publications
In December 1981 , an epizootic of the protozoan parasite Ichthyophthirius multifiliis killed an estimated 18 million killifish Orestias spp. in Lake Titicaca, a high-altitude tropical system. Of the dead fish collected, 93% were adult O. agassii, a commercially important species that is abundant in the littoral zone. Juvenile Orestias spp., pelagic species, and some other littoral zone fis hes were slightly affected. lchthyophthirius multifiliis was probably introduced with exotic fishes brought to Lake Titicaca in the 1940s and 1950s.
Microhabitat Selection And Diel Movements Of Juvenile Rainbow Trout (Salmo Gairdneri) Introduced Into Mid-Elevation Reservoirs In Utah, Wayne A. Wurtsbaugh, Roger Tabor
Microhabitat Selection And Diel Movements Of Juvenile Rainbow Trout (Salmo Gairdneri) Introduced Into Mid-Elevation Reservoirs In Utah, Wayne A. Wurtsbaugh, Roger Tabor
Watershed Sciences Faculty Publications
The distribution and movement patterns of fingerling rainbow trout stocked into reservoirs in Utah were investigated with · SCUBA observations and by vertical gill netting. For several weeks after stocking, fingerling trout (ca. 80 mm standard length) were strongly oriented to the shore, and selected habitats providing cover. During the underwater observations, no fish were seen below depths of 2 meters. Two weeks after stocking, the fingerlings were most abundant under docks near where they were planted, indicating that dispersal was relatively slow. Jacob's electivity indices for natural substrates in water 0-1.5 meter deep were in sand, gravel, cobble, boulders …
Importance Of Predation By Adult Trout On Mortality Rates Of Fingerling Rainbow Trout Stocked In East Canyon Reservoir, Utah, Wayne A. Wurtsbaugh
Importance Of Predation By Adult Trout On Mortality Rates Of Fingerling Rainbow Trout Stocked In East Canyon Reservoir, Utah, Wayne A. Wurtsbaugh
Watershed Sciences Faculty Publications
Personnel from Utah State University, working in cooperation with the Utah Division of Wildlife Resources and the Utah Cooperative Fish and Wildlife Research Unit, are attempting to determine various sources of mortality of fingerling rainbow trout (Salmo gairdneri) stocked into mid-elevation reservoirs in the State. Returns of planted fish are often much below desired levels. Angler surveys indicate that in East Canyon Reservoir, fishermen harvest only about 30% of the fingerling trout stocked, and this is a much higher return than in many other waters.
The Vertical Distribution And Feeding Chronology Of Larval Bear Lake Sculpin (Cottus Extensus) In Bear Lake, Utah-Idaho, D. Neverman Devroy, Wayne A. Wurtsbaugh, S. Ohlhorst
The Vertical Distribution And Feeding Chronology Of Larval Bear Lake Sculpin (Cottus Extensus) In Bear Lake, Utah-Idaho, D. Neverman Devroy, Wayne A. Wurtsbaugh, S. Ohlhorst
Watershed Sciences Faculty Publications
Preliminary sampling in Bear Lake, Utah/Idaho, with bottom trawls and larval fish nets indicate
Growth And Activity Of Juvenile Mosquitofish: Temperature And Ration Effects, Wayne A. Wurtsbaugh, J. Cech
Growth And Activity Of Juvenile Mosquitofish: Temperature And Ration Effects, Wayne A. Wurtsbaugh, J. Cech
Watershed Sciences Faculty Publications
The effects of constant temperatures (10, 15, 20, 25, 30, and 35 C) and ration size on the growth rates and activity of juvenile mosquitofish Gambusia affinis (mean wet weight, about 20 mg) were measured in laboratory experiments. On ad libitum rations of Tubifex spp. worms, food-consumption rates of mosquitofish were very high, ranging from 7% dry body weight/day at 10 C to 83%/day at 35 C. Growth increased from 0% dry body weight/day at 10 C to 21%/day at 30 C and declined slightly at 35 C. Gross efficiencies (100 growth/food consumption) increased from 0 at 10 C to …
Effect Of Fish Size On Prey Size Selection In Gambusia Affinis, Wayne A. Wurtsbaugh, Joseph J. Cech Jr., James Compton
Effect Of Fish Size On Prey Size Selection In Gambusia Affinis, Wayne A. Wurtsbaugh, Joseph J. Cech Jr., James Compton
Watershed Sciences Faculty Publications
Food size selection of the mosquitofish , Gambusia affinis affinis. was measured in aquaria using juvenile stages of the mosquito, Clllex tarsalb;, as prey. Fish size varied from recently born fry to large adult females. Food size selection was positively correlated with fish size. Mosquitofish fry (6-8 111m standard length) attacked and ate primarily first and second instar larvae. Fry attacked larger instars, but attack success on these was low (0 - 50%). Fish larger than 20 mm attached primarily pupae and third and fourth instar larva. No first instar mosquitoes were eaten. Attack success for these fish was above …
Mass Marking Of Mosquitofish: Preliminary Results, Bruce Vondracek, Wayne A. Wurtsbaugh, Joseph J. Cech Jr.
Mass Marking Of Mosquitofish: Preliminary Results, Bruce Vondracek, Wayne A. Wurtsbaugh, Joseph J. Cech Jr.
Watershed Sciences Faculty Publications
Three marking techniques were tested to determine their applicability for mosquitofish. Tetracycline drugs and DC Ar administered in the diet successfully marked laboratory-cultured mosquitofish, but exposure to direct sunlight in outdoor tanks resulted in the rapid disappearance of the marks. Preliminary data on fluorescent marks from a polystyrene pigment in a melamine-sulfonamide-formaldehyde resin forced into the dermal ,tissue with compressed air are more promising.
A t an optimal deliver pressure of 7.3 m Hg (140 p.s.i.) and spraying time of 15 sec., marking percentage is maximized and fish mortality is minimized. Mark retention time was up to 80 days in …
The Relationship Of Food Conversion Efficiency And Growth Potential In Juvenile Mosquitofish, Gambusia Affinis, Joseph J. Cech Jr., Michael J. Massingill, Wayne A. Wurtsbaugh
The Relationship Of Food Conversion Efficiency And Growth Potential In Juvenile Mosquitofish, Gambusia Affinis, Joseph J. Cech Jr., Michael J. Massingill, Wayne A. Wurtsbaugh
Watershed Sciences Faculty Publications
New information concerning respiratory metabolic rates of juvenile mosquitofish (i = 915 mg 02 kg-1 h-1 at 20° C) was applied to existing data on mosquitofish respiration and combined with findings on growth and food consumption rates to determine percentages of net ingested energy used for growth and respiration over a 10- 35° C temperature range. The energy percentage used by mosquitofish for respiration was minimized at 25-30° C while that used for growth (= food conversion efficiency) was maximized at the same temperature. A calculated growth potential index, derived from an overall energy balance equation, was also maximized at …
Laboratory Apparatus For Providing Diel Temperature Regimes For Aquatic Animals, Wayne A. Wurtsbaugh, G. Davis
Laboratory Apparatus For Providing Diel Temperature Regimes For Aquatic Animals, Wayne A. Wurtsbaugh, G. Davis
Watershed Sciences Faculty Publications
In studies of the effects of elevated temperature on aquatic organisms, little emphasis has been placed on modeling the fluctuating temperatures to which organisms are exposed in nature. To some extent this may be related to problems of design and maintenance of apparatus for fluctuating temperature control. The complexity of apparatus used to provide cycled temperatures has ranged from manually controlled valves for introducing water of different temperatures into aquariums (Kelso 1972), to a complex and expensive feedback system, regulated by rotating cams, that controls the temperature of influent water (Honeywell Cam Programmer Thermometers, Fort Washington, Pennsylvania). To facilitate studies …
Food And Distribution Of Underyearling Brook And Rainbow Trout In Castle Lake, California, Wayne A. Wurtsbaugh, R. Brocksen, C. Goldman
Food And Distribution Of Underyearling Brook And Rainbow Trout In Castle Lake, California, Wayne A. Wurtsbaugh, R. Brocksen, C. Goldman
Watershed Sciences Faculty Publications
A difference was found in the summer distribution of underyearling brook trout, Salvelinus fontinalis (Mitchill), and planted rainbow trout, Salmo gairdneri Richardson, in Castle Lake, California. Brook trout underyearlings oriented to the bottom and were found primarily in shallow water on the eastern shore of the lake near springs. The rainbow trout underyearlings were more pelagic and were found in the littoral areas along the entire shoreline. Gravimetrically, the food eaten during the summer by brook trout underyearlings was 13% terrestrial, 11% limnetic, and 76% benthic. Rainbow trout ate 15% terrestrial, 15% limnetic, and 70% benthic food. In summer, rainbow …