The annual energy budget was determined for the rainbow trout and kokanee populations of a small (13.3 ha) British Columbia lake. Population size of the rainbow trout aged 1⁺ and older was 4000 based on a 55 catch-day Schnabel estimate. Number of kokanee present in the lake (9000) was based on the ratio of occurrence of kokanee to rainbow trout (2.25:1) in catch. Monthly instantaneous growth and mortality rates were applied to each age group. Seasonal change in gonad weight as a percentage of body weight was similar in both species (ovaries 0.5%-13%, testes 0.5%-4%). Sex ratios were generally even in kokanee but there was a higher percentage of females (57.7%) in the rainbow trout. The relationship between egg number per female (F) and fork length (L) was calculated (rainbow trout, F = 18.7 L•⁹⁵⁹; kokanee, , F = 2.84 L¹•⁴¹⁴). The percent volume of each major food item was determined by stomach analysis. In only one month (May) was the food item of highest % volume the same in both species. Seasonal change in energy content of the food was estimated. Calculation of daily ration (as a percentage of body weight) was based on turnover rates (y) of food consumed at different temperatures (y = .545 e•º⁹¹x, where x is in °C). Feeding experiments using natural foods indicated assimilation efficiencies of 85.5%. Continuous (20 hr) measurement of routine metabolism of individual fish was made with a respirometer situated in Marion Lake, between, August 1967 and October 1968. Rate of oxygen uptake (Q) in ml/hr, at 15 °C was plotted against weight (W) in kg (Q = 62.6 W•⁷⁶). To determine the amount of energy trapped within the two populations, sample fish were dried (gonads separately) and burned in a calorimeter. The percent moisture of the fish was 74-78% during the year with marked increases at spawning time (rainbow 82%, kokanee 88%). The seasonal changes in energy content of immature fish were small (rainbow trout 6050-6200 cal/ash-free g; kokanee 6150-6300 cal/ash-free g). However mature fish underwent sharp reductions in energy content prior to spawning (rainbow trout 6100 to 5500 cal/ash-free g; kokanee 6100 to 5^00 cal/ash-free g). The pattern of seasonal change in energy content of the gonads was similar to that of the body. Average biomass present in the lake was 1.53 x 10⁴ Kcal/ha (12.3 kg/ha) for the rainbow trout, and 2.23 x 10⁴ Kcal/ha (16.6 kg/ha) for the kokanee. Annual production for the two populations was 2.81 x 10⁴ Kcal/ha. The ratio of production to biomass for rainbow trout was 0.80, and for kokanee was 0.71. / Science, Faculty of / Zoology, Department of / Graduate

The effect of S.W. on the osmoregulatory processes of Rainbow trout was studied. Rainbow trout were monitered for various acid--ba.se and respiratory parameters during F.W. - S.W. transfer. Plasma Cl⁻, total CO₂ and HCO₃⁻ concentrations were measured, as well as blood pH, Pa0₂ and PC0₂- V02₂, VG, VCO₂, and VH⁺ were calculated from the measured parameters. During the exposure to S.W. for 3 hours none of the measured variables changed significently, indicating that the Rainbow trout is indeed euryhaline. It appears that unlike the goldfish the trout has a branchial Cl⁻/HCO₃⁻ exchange diffusion pump that is of small capacity, because changes in the external concentrations of CI⁻ and HCO₃⁻ did not affect internal levels of these ions. Raising external Cl⁻ levels would cause a lowering in plasma HCO₃⁻ if there was a Cl⁻/HCO₃⁻ exchange diffusion pump in the gills. A second group of experiments involved the use of Cl⁻ to measure Cl⁻ fluxes in the gills of intact trout. Injections of HCO₃⁻ into the fish did not stimulate Cl⁻ efflux, indicating that if there is a Cl⁻/HCO₃⁻ exchange diffusion pump, it is of small capacity. Gill carbonic anhydrase levels were measured in the gills of F.W. and S.W. trout, S.W. and F.W. coho, and goldfish. Goldfish have a high level as does the S.W. coho. Carbonic anhydrase catalyses the formation of HCO₃ from C02 for the Cl⁻/HCO₃⁻ pump, and is thus indicative of the importance of the pump in Cl⁻ and HCO₃⁻ fluxes.. The significance of the differences in the ionic pumps of trout, coho, and goldfish are discussed in relation to their life histories. Trout having a flexible osmoregulatory system (being euryhaline) while the coho and goldfish are more specialised being essentially stenohaline. / Science, Faculty of / Zoology, Department of / Graduate

Fish raceways of different cross-sectional shapes were compared in biological and hydraulic tests. Raceways of rectangular and circular cross-section were used. Two types of circular raceways were studied, one with a smooth wall, made of PVC, and one with a corrugated wall, made of galvanized steel that had been painted. The biological tests consisted of comparing the weight gain of rainbow trout (Salmo gairdneri) fingerlings (initial weight 6.0 g) held in the different raceways for 69 days. The fish in the painted corrugated steel raceway (final weight 25.6 g) grew more than those in the rectangular (final weight 22.9 g) and PVC (final weight 20.2 g) raceways (significant at α = 0.05). Very high stocking densities (130-139 kg/m³) achieved at the end of the experiment. Critical concentrations of dissolved oxygen or ammonia had not been reached at this point. Two types of hydraulic tests were done. One consisted of flow visualization studies in which a dye, malachite green, was introduced into the raceway and its movement observed and recorded photographically. In the second hydraulic test, the concentration of malachite green in the effluent was measured at various times after the introduction of the dye. These data were then used to obtain residence time distributions for the various raceways. No major differences were found between the hydraulic characteristics of the raceways tested. A biological test using unpainted galvanized corrugated steel raceways was also carried out. Rainbow trout fingerlings (3.6 g) were placed in galvanized raceways that had been flushed for 64 days. The fish were left in the raceways for 29 hours. During this time, 48% of the fish died. The survivors were transferred to fiberglass tanks where an additional 27% of the fish died over the next 50 hours (2 days). / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

No description available.

No description available.

Two types of estrogen binding sites were found in the rainbow trout liver cytosol, using the equilibrium binding assay. The higher affinity, lower capacity type I site had a Kd range of 0.53-5.9 nM and a concentration range of 14-95 pmoles/g protein. The lower affinity, higher capacity type II sites had a Kd range of 65-265 nM and a concentration range of 20-180 pmoles/g protein. These estrogen binding sites are both bound by ^3H-moxestrol. The estrogen binding sites in the serum were also examined and two components were found with the higher affinity component having a Kd of 2.63 nM and a concentration of 25 pmoles/g protein while the lower affinity component had a Kd of 79 nM and a concentration of 200 pmoles/g protein. However, these estrogen binding components are unable to bind the synthetic estrogen, DES, and therefore cannot account for either of the binding components found in the liver cytosol which bind DES as readily as 17β-estradiol. The cytosol estrogen binding sites bind non-estrogens in addition to estrogens. Sucrose gradient centrifugation of the cytosol yielded two estrogen binding peaks, one at 4.4S, the other at 3.7S. The heavier peak contained binding sites able to bind progesterone as well. Gel filtration of the cytosol also resulted in two peaks, one at 43,000 daltons, the other at 33,000 daltons. Again the heavier peak could be partially competed out by progesterone. The half life of these binding components was 60 minutes at 37°C, while no decrease in binding was observed after 4 hours at either 0 or 12 0 c. After 17β-estradiol treatment in vivo type I sites (relative to type II sites) were 74% depleted after 8.5 hours and 40% depleted after 24 hours. Finally, o,p'-DDT and p,p'-DDT, components of technical grade preparations of the insecticide DDT were both able to compete for estrogen binding sites in the rainbow trout liver cytosol and therefore may be able to affect the expression of estrogen inducible genes. / Thesis / Master of Science (MSc)

Electrofishing, which is widely used for fish collection, is a procedure that is often followed by handling and air exposure before the fish are released. Although the consequences of electrofishing are not fully known, some studies suggest that physical damage such as skeletal injury and mortality can result. Physiological disturbances resulting from stimulation of the stress axis and impaired ventilation have also been reported following electroshock. In the present study, rainbow trout treated with pulsed DC electroshock, in fact, showed no evidence of direct mortality, and skeletal damage was only induced under the most severe conditions. Physiological disturbances in the absence of physical damage consisted of a lactacidosis and stimulation of the stress response. The lactacidosis was likely induced by tetany during immobilization and impaired ventilation during immobilization and early recovery. These disturbances, which persisted for at least 4h, were greater than those reported following DC electrofishing. They were, in fact, similar in magnitude and duration to 2-3 min bout of exhaustive exercise. Swim performance following pulsed DC electroshock was also impaired for at least 1 h. If fish were air exposed immediately following pulsed DC electroshock the stress response and lactacidosis tended to be more severe and swim performance was further impaired. / Thesis / Master of Science (MSc)

The underlying problems associated with the development of the biotic ligand model (BLM) for prediction of silver toxicity, and its associated physiological and toxicological endpoints, were investigated at a mechanistic, physiological level in juvenile rainbow trout. An equilibrium level of silver accumulation at the gills is achieved over time during flow-through exposures. The pattern of peak and decline in accumulation during static exposures is due to a decrease in the bioavailability of Ag⁺ because of complexation by organic carbon produced by the fish, a consequence of the use of a static exposure system. The decrease in bioavailability leads to a decline in apical silver uptake and together with constant basolateral silver export, a peak and decline in gill silver accumulation. Inhibition of carbonic anhydrase (CA) by silver is responsible for the early decline in active Na⁺ uptake at the gills during flow-through silver exposure, while Na⁺K⁺-ATPase inhibition is associated with the later decline in uptake. CA activity is inhibited early during silver exposure when Na⁺ and Cl⁻ uptake are decreasing but Na⁺ K⁺ ATPase activity is not inhibited until later. The implication of the data that the rate limiting step in the movement of Na⁺ and Cl⁻ across the gill epithelium is the movement across the apical membrane, as well as the identical time course and degree of Cl⁻ and Na⁺ uptake inhibition provide additional evidence for a role of CA inhibition in the early decline in Na⁺ uptake. A relationship exists between short-term gill silver accumulation and inhibition of Na⁺ uptake. There is also a relationship between silver accumulation on the gills after 3 h, as well as after 24 h, and 96 h mortality. Together, the results of this thesis indicate that short-term gill silver accumulation is an appropriate endpoint for the prediction of acute silver toxicity in freshwater fish, lending support to the current toxicological version of the silver BLM. These results also indicate that the predictive capabilities of the current physiological BLM may be improved by using Na⁺ uptake inhibition rather than Na⁺K⁺-ATPase inhibition as an endpoint to predict acute silver toxicity. / Thesis / Master of Science (MS)

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 52-60). Also available on the World Wide Web.

Before 1980, Ashurst Lake had an exceptionally productive rainbow trout fishery. More recently, Ashurst has become turbid and trout growth rates have declined substantially. The growth, condition, and food habits of a single cohort of rainbow trout was followed from May 1985 until October of 1986. The first year, trout in Ashurst grew from 66 mm to 164 mm in 5 months. Growth reached an average of 24 mm/month from June to September, a time when trout fed primarily on Daphnia. By July of the second year, growth had stopped and condition declined substantially in conjunction with a change in their diet from Daphnia to crayfish and minnows. The decrease in growth rate was attributed to a decrease in the food base coupled with hampered foraging abilities of rainbow trout in water with high turbidity. High tubidity may have resulted from erosion of the surrounding watersheds.