Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

Thesis (M.S. in genetics and cell biology)--Washington State University, May 2008. / Includes bibliographical references (p. 29-32).

Thesis (M.S.)--Oregon State University, 1986. / Typescript (photocopy). Includes bibliographical references (leaves 50-55). Also available on the World Wide Web.

Following a study of normal reproductive behavior of fathead minnows, Pimephales promelas, experiments were conducted to determine the stability/variability of behavior by sexually mature, territorial males under a variety of manipulated conditions. Collectively, these experiments indicate that although the individual behaviors of fathead minnows appear to be quite variable, the overall process, reproductive behavior, is stable.

Adequate levels of dissolved oxygen (DO) are essential to the health of most aquatic organisms. While diel fluctuations in DO concentration are a normal occurrence in aquatic ecosystems, anthropogenically-produced periods of prolonged hypoxia have the potential to cause changes in growth, reproduction and behaviour in animals. My thesis examined reproductive behaviour and physiology of fathead minnows (Pimephales promelas) following exposure to several concentrations of dissolved oxygen. Using a custom-built system that was able to maintain DO concentrations at precise levels, reproductive performance was analyzed under 3.5 mg/l, 4.5 mg/l, 5.5 mg/l and a control of 7.5 mg/l of DO. A second experiment evaluated reproductive performance at 5.0, 5.7, 6.5 and 7.5(control) mg/L.<p> Breeding attempts ceased altogether at 4.5 mg/l and lower. At higher concentrations, the effects of DO on reproductive output were contradictory between experiments. When DO was maintained at 5.5 mg/L in the first experiment, egg production was lower than in the controls. When DO levels of 5.7 mg/L were used in the second experiment, egg production was higher than in the controls. Courtship behaviour decreased significantly compared to the control at DO levels of 4.5 mg/L and lower. No significant differences were observed between treatments in morphometrics, survival, larval deformities, sex steroid levels, vitellogenin levels, hatching success, egg size, fertility, or gonad histology.<p> The results of this study demonstrate that reproductive behaviour may represent a sensitive early marker of reproductive impairment in fathead minnows. Inconsistencies between the two experiments suggest a possible hormetic effect in response to depressed DO in fathead minnows. My results have important implications with respect to Canadian water quality guidelines and applications in the restoration of aquatic systems with lowered DO due to human activities.

Adequate levels of dissolved oxygen (DO) are essential to the health of most aquatic organisms. While diel fluctuations in DO concentration are a normal occurrence in aquatic ecosystems, anthropogenically-produced periods of prolonged hypoxia have the potential to cause changes in growth, reproduction and behaviour in animals. My thesis examined reproductive behaviour and physiology of fathead minnows (Pimephales promelas) following exposure to several concentrations of dissolved oxygen. Using a custom-built system that was able to maintain DO concentrations at precise levels, reproductive performance was analyzed under 3.5 mg/l, 4.5 mg/l, 5.5 mg/l and a control of 7.5 mg/l of DO. A second experiment evaluated reproductive performance at 5.0, 5.7, 6.5 and 7.5(control) mg/L.<p> Breeding attempts ceased altogether at 4.5 mg/l and lower. At higher concentrations, the effects of DO on reproductive output were contradictory between experiments. When DO was maintained at 5.5 mg/L in the first experiment, egg production was lower than in the controls. When DO levels of 5.7 mg/L were used in the second experiment, egg production was higher than in the controls. Courtship behaviour decreased significantly compared to the control at DO levels of 4.5 mg/L and lower. No significant differences were observed between treatments in morphometrics, survival, larval deformities, sex steroid levels, vitellogenin levels, hatching success, egg size, fertility, or gonad histology.<p> The results of this study demonstrate that reproductive behaviour may represent a sensitive early marker of reproductive impairment in fathead minnows. Inconsistencies between the two experiments suggest a possible hormetic effect in response to depressed DO in fathead minnows. My results have important implications with respect to Canadian water quality guidelines and applications in the restoration of aquatic systems with lowered DO due to human activities.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 42-46).

Natural selection should favour host defenses that reduce a host’s exposure to parasites or reduce their negative effects. One strategy that resolves the substantial costs of host immunity and/or tolerance is to avoid infective stages altogether. For fish, behavioural avoidance is well-known for defense against aquatic predators, but it is poorly known for defense against parasites. I used a model system that is amenable to experimental manipulation to test the behavioural avoidance hypothesis for fathead minnows exposed to the larvae of two of their common flatworm parasites. First, I showed that minnows exposed to a liver encysting trematode, Ornithodiplostomum sp. showed an increase in lipid peroxidation, an indicator of oxidative stress, persisting through worm development. Three lines of evidence provided support for the behavioural avoidance hypothesis. First, shoal area decreased in groups of minnows exposed to O. ptychocheilus cercariae compared to those exposed to cues from other aquatic threats. Second, average worm numbers were 50 % lower in fish confined to artificial shoals compared to non-shoaling minnows, indicating that shoaling reduces risk of exposure. The third experiment showed that minnows within the centre of shoal reduced their risk of infection by 67%. Taken together, these results demonstrate a cost of trematode infection on minnows, that minnows can detect infective larvae within the water column, and that social living reduces a hosts’ risk of exposure. / xi, 84 leaves : ill. ; 29 cm

Sertraline is a selective serotonin reuptake inhibitor (SSRI) that is widely used for the treatment of depression and anxiety. Due to the abundant therapeutic use of sertraline, low levels have been detected in municipal wastewater effluents suggesting that aquatic organisms may be exposed. The purpose of this study was to evaluate the steroidogenic effects of sertraline on larval (FHM) and adult female fathead minnows (FFHM), Pimephales promelas. Larval FHM were exposed to 0.1, 1, and 10 µg/L sertraline for 28 days and analyzed via RT-qPCR for differential expression of 11β-Hydroxysteroid dehydrogenase (11β-HSD), 20β-Hydroxysteroid dehydrogenase (20β-HSD), aromatase (CYP19), and nuclear thyroid receptor alpha (TRα). FFHM were exposed to 3 or 10 µg/L sertraline for 7 days with the brain and ovary excised at exposure termination. Juvenile FHM exposed to 0.1 μg/L sertraline had a significant upregulation of both 20β-HSD and TRα. FFHM exposed to 10 µg/L sertraline had a significant upregulation of 11β-HSD expression in brain tissue, while no steroidogenic changes were observed in the FFHM ovary. Similarly, in FFHM brain tissue, CYP19 and 20β-HSD expression levels were significantly higher in fish exposed to 10µg/L sertraline compared to control. The significance of these findings with respect to survival, growth and reproduction are currently unknown, but represent future research needs.

Avoidance to a blend of four metals (relative proportions: 1.00 copper, 0.54 chromium, 1.85 arsenic, 0.38 selenium) was determined for schools of fathead minnows (<i>Pimephales promelas</i>) in a laboratory avoidance chamber, an artificial stream and in a natural stream setting on a seasonal basis during continuous exposure to low levels of the metal blend for up to 9 months. Laboratory avoidance responses were determined seasonally during 12 months of laboratory holding for unexposed (control) fish and two levels of metal blend exposure in a steep gradient laminar flow chamber. Toxicity of the metal blend was determined for laboratory and field, control and metals acclimated fish. Unexposed fish avoided very low levels of the blend (29 ug/L total metals). Fish exposed to low levels of the blend (49 ug/L total metals) for 3 months failed to avoid levels equal to 5X holding exposure levels. Fish exposed to higher levels of the blend (98 ug/L total metals) preferred elevated levels (3X holding exposure) after 3 months exposure, mildly avoided 5X holding levels after 6 months exposure and were not responsive to levels approaching 10X holding exposure after 9 months continuous exposure. Activity was not affected by long term exposure. Field avoidance responses were determined seasonally during 7 months of field laboratory holding in New River water for unexposed (control) fish and exposed (98 ug/L total metals) fish in a modified artificial stream supplied with raw New River water. Unexposed fish avoided 71.1 and 34.3 ug/L total metals in spring (3 months holding) and summer (6 months holding) respectively. After 3 months exposure in New River water, fish did not respond to metal blends as high as 1,470 ug/L total metals. In-stream avoidance responses were determined in the summer for unexposed (control) and exposed I (98 ug/L total metals) fish in a Adair Run, a second order tributary to the New River. Unexposed fish avoided 73.5 ug/L total metals in Adair Run. After 3 months exposure, in New River water fish did not respond to metal blends as high as 2,940 ug/L in Adair Run. Water hardness, turbidity and physical setting are implicated as possible causative factors for differences between control fish responses tested in different seasonal and locations. Fish exposed to the high level exposure in the laboratory had a 96-hr LC50 value 1.25X higher than laboratory control fish. Laboratory control fish avoided metals levels at 0.4% of their 96-hr LC50. Fish exposed to the metals blend in the field had a 96-hr LC50 value 1.41X higher than field control fish. Field control fish avoided metals levels between 0.7 and 2.5% of their 96-hr LC50 depending upon test location and season. There was no difference between the 96-hr LC50s of laboratory vs field control fish or between laboratory vs field exposed fish. Optimum statistical methods for analyzing avoidance behavior in schooling fish were developed. / Ph. D.