Accurate measurements of energy content and body composition are essential to effectively assess the well-being of fish. Bomb calorimetry and proximate analysis are currently the most dependable and accurate methods to estimate energy content and body composition. However, bioenergetic studies that employ the traditional methodology necessitate the killing of fish to determine physiological composition and energy content in a target tissue. The killing of the individual negates the ability for repeated measures on the same individual, and also suppresses compositional studies involving endangered or threatened species. Recent research has shown Bioelectrical Impedance Analysis (BIA), a quick, easy-to-use, non-invasive, and most importantly, non lethal technique to be an effective method for estimating the proximate composition and energy content of fish. The focus of this research is to evaluate the capability of BIA to accurately assess the bioenergetics of juvenile rainbow trout (Oncorhynchus mykiss), and to develop species-specific indices to predict energy content, total body water and dry mass. To do this, juvenile rainbow trout were subjected to one of three ration regimes: maintenance (0.4 % bw/day), optimum (1.9 % bw/day) and satiation (3.4 % bw/day) for 90 days. Subsamples from each treatment were taken every 30 days to be subjected to BIA testing. Tissue samples were collected from the subsampled trout for future caloric and compositional analysis via bomb calorimetry and proximate analysis. It was found that BIA demonstrated a strong predictive relationship with regard to energy content (r2 = 0.90), total body water (r2 = 0.89) and dry mass (r2 = 0.80). BIA was also able to successfully reflect a notable statistical difference between treatments with regard to total energy content, energy density, total body water, dry mass. These results, along with much of the existing literature, indicate that BIA may be an accurate and reliable tool to estimate the bioenergetics and proximate composition of fish. / UOIT

Climate change may lead to declines in lake trout (Salvelinus namaycush) populations and change the structure of the ecosystem in which they live. The lake trout is a keystone species in ecosystems of northern temperate lakes and these declines may subsequently reduce the genetic diversity found in these salmonids. Populations that contain greater genetic variation may have an increased capacity to adapt to changes in the ecosystem. Therefore, an understanding of the genetic diversity found in lake trout populations is required for their effective conservation and management. As a result, this study aimed to examine the genetic diversity and phylogeography of lake trout populations in north central Canada.<p>The genetic diversity of lake trout from 19 lakes in Saskatchewan was examined using partial regions of the ND2 and ND5 mtDNA genes. A total of 607 tissue samples were analyzed using PCR-based single stranded conformation polymorphism (SSCP) and DNA sequencing. Although the ND5 gene fragment had minimal intraspecific variation, eleven sequence types were detected in the ND2 gene. Each sequence type differed in relative frequency between and among the lake trout populations sampled. <p>One particular southern lake trout population, Crean Lake, had markedly different genetic composition in comparison to other lakes in the region. In the 1950s and 1960s, Crean Lake was stocked with lake trout from neighbouring Wassegam Lake in an attempt to increase population numbers. The sequence types of Crean Lake trout and their relative frequencies were dramatically different to those in Wassegam Lake. This suggests that the stocked fish may have been unsuccessful in their establishment/reproduction within Crean Lake. Lake trout from this lake also contained the highest frequency (44%) of rare ND2 sequence type B. Sequence type B was only detected in one other lake (La Ronge), at a very low frequency. <p>The mutational changes in the eleven ND2 mitochondrial DNA sequence types represented three different amino acid sequence types. Substitutions of Threonine and Isoleucine occurred, resulting in two polar amino acids with much different hydropathy indexes. This may affect the tertiary structure of the protein, possibly indicating functional differences. Functionally different proteins may be exhibiting characteristics that allow lake trout to flourish in their environment. <p>The fragments of both the ND2 and ND5 genes proved to be valuable for phylogenetic analyses within the Salmonidae. The genetic markers established in the present study provide the basis for future work on population genetics of lake trout. It would be advantageous to broaden the area of study in order to compare the genetic diversity found within the study area to other regions of Canada. This would determine whether the genetic diversity detected in this study is significantly greater than in other populations at a national scale. Management strategies should ultimately attempt to conserve the genetic diversity found within the lake trout populations of north central Saskatchewan.

Graduation date: 1993

Trout-perch, Percopsis omiscomaycus, were collected during the sample months June through September, 1973, in southern near-shore waters of Lake Michigan near Michigan City, Indiana. Three transects were sampled at depths of 1, 5 and 15 m using an otter trawl and a nylon bag seine. Fish were collected mainly at midnight because of diurnal migration and feeding demonstrated by trout-perch.Food habit analysis showed Chironomus spp. and Pontoporeia affinis to be the major food items of the trout-perch. Other organisms of lesser importance as food include: Eurycercus lamellatus, Eurytemora affinis, Chironomid pupae and alewife eggs, Alosa pseudoharengus.A combined monthly analysis of trout-perch food habits showed zooplankton and alewife eggs as important food items in, June decreasing.in importance throughout the remaining sample months. Amphipoda, primarily Pontoporeia affinis, was of greatest importance in June decreasing in percent volume in July and August and increasing in volume again during the September sample period. Chironomid larvae, primarily Chironomus spp., was a minor food source in June increasing to major proportions during the remaining sample months.Monthly food habits comparing size groups showed -greatest utilization of zooplankton as a food source by Group 1 (20 - 49 mm) trout-perch during the sample period June; decreasing as trout-perch size increased. There was a marked decrease in zooplankton consumption in the remaining sample months for combined size groups.Monthly food habits comparing size groups showed the greatest utilization of Amphipoda during the June sample month. Size Group III (100 - 139 mm) trout-perch consumed Amphipoda in largest quantities throughout the combined study period.Monthly food habits for Insecta consumption comparing size groups were at lowest volume in June, increasing in volume during the remaining sample months. Chironomus spp. was the major food item consumed by trout-perch.Ball State UniversityMuncie, IN 47306

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

Fluoxetine (FLX), the active ingredient of Prozac™, is a member of the selective serotonin reuptake inhibitor (SSRI) class of anti-depressant drugs and is present in aquatic environments worldwide. Previous studies reported that FLX is an endocrine disruptor in fish, bioconcentrating in tissues including the brain. Evidence implicates that serotonin influences the activity of the hypothalamo-pituitary-interrenal (HPI) stress axis, thus exposure to FLX may disrupt the teleost stress response. This study examined in vitro cortisol production in rainbow trout (Oncorhynchus mykiss) head kidney/interrenal cells exposed to FLX and 14C-pregnenolone metabolism in head kidney microsome preparations of FLX-exposed trout. Results indicated that cells exposed in vitro to increasing concentrations of FLX had lower cortisol production and cell viability (versus control) and microsomes isolated from trout exposed to 54 μg/L FLX had higher pregnenolone metabolism versus those of control and low FLX-exposed (0.54 μg/L) trout.

The physiological responses to stressor exposure can be broadly grouped into the organismal and the cellular stress responses. The organismal stress response involves the release of hormones into general circulation, while the cellular stress response involves the synthesis of proteins, the most important being the heat shock proteins (HSPs), which play a role in maintaining protein homeostasis. Elevated HSP70 expression in response to stressors has been demonstrated in trout (Oncorhynchus mykiss) red blood cells (RBCs). The ease of repeated sampling of blood suggests the possibility of using this tissue as a non-lethal marker of cellular stress in fish. This study tested the hypothesis that stressor exposure will elevate HSP70 expression in trout RBCs and the role of stress hormones in mediating this response. Acute heat shock exposure (+12oC) significantly elevated plasma cortisol, glucose and lactate levels in heat shocked fish over 24 h. A tissue-specific response was seen in HSP70 expression in liver, brain, gill and RBCs. To enable measurement of RBC HSP70 concentrations, an enzyme-linked immunosorbent assay (ELISA) was developed using a commercially available rabbit anti-salmon HSP70 and a recombinant chinook salmon (Oncorhynchus tshawytscha) HSP70. To determine effects of chronic exposure, two studies were conducted exposing trout to either cadmium (0, 0.75 or 2.0 µg/L over 28 d) or municipal wastewater effluent (0, 20 or 90% over 14 d). However, neither exposure elicited a significant HSP70 response. Effects of stress hormones on RBC HSP70 levels were tested by exposing cells in vitro to either cortisol (10 and 100 ng/mL) or epinephrine (10 nM) with or without heat shock. Heat shock elevated HSP70 content in trout RBCs but no modulation by stress hormones was seen. It was shown for the first time that RBCs release HSP70 content into the medium in response to an acute heat shock and this release is attenuated by stress hormones. Overall, HSP70 levels in RBCs have the potential to be a reliable non-lethal marker of acute cellular stress effects in fish. The release of HSP70 from RBCs leads to the hypothesis that HSP70 may also have an extracellular role in fish, and warrants further study.

β2-microglobulin (β2m) exists free of the major histocompatibility complex class I (MHC I) receptor in many bodily fluids. The amount of protein present in these fluids has been found to be a useful prognostic marker for various diseases but outside of its practical value not much is known about this form of β2m. In fish, soluble β2m has not been studied at all. Another unknown in fish is the effects that plants lectins might have on naturally carnivorous species in aquaculture. These plant proteins which bind to specific sugar groups found on cells have been shown to have a multitude of gastrointestinal and immune effects in mammals and can be found in the plant products being fed to carnivorous, cultured fish making them possible toxicants. The two studies of this thesis set out to pioneer knowledge on these subjects using rainbow trout as a model. The first investigation inspected the various body fluids of these fish for their free β2m content. Soluble β2m was found to be present in the plasma, the seminal fluid, ovarian fluid, and the mucus of the skin and intestines. This distribution shows that β2m could indeed make a good biomarker, not only for disease but also for pheromone release and alludes to some possible functions of soluble β2m while opening the way for future research on this form of the protein. The second study looked at the effects of lectins on the gut of rainbow trout by treating RTgutGC, an intestinal epithelial cell line derived from trout, with plant lectins from wheat (WGA) and soybean (SBA), among others. This study found WGA to be a potent inducer of morphological and cytotoxic effects in these cells while other lectins and plant factors were not. WGA was also observed to effect the expression of β2m and the α-chain of the MHC I receptor. This work suggests WGA ingested by trout through the wheat in their diet might be causing them harm and should be studied further. It is also interesting that both studies related β2m to the intestines of trout. This could allow soluble β2m to serves as a marker of WGA’s effect or for WGA to aid in the study of free β2m.

Climate change may lead to declines in lake trout (Salvelinus namaycush) populations and change the structure of the ecosystem in which they live. The lake trout is a keystone species in ecosystems of northern temperate lakes and these declines may subsequently reduce the genetic diversity found in these salmonids. Populations that contain greater genetic variation may have an increased capacity to adapt to changes in the ecosystem. Therefore, an understanding of the genetic diversity found in lake trout populations is required for their effective conservation and management. As a result, this study aimed to examine the genetic diversity and phylogeography of lake trout populations in north central Canada.<p>The genetic diversity of lake trout from 19 lakes in Saskatchewan was examined using partial regions of the ND2 and ND5 mtDNA genes. A total of 607 tissue samples were analyzed using PCR-based single stranded conformation polymorphism (SSCP) and DNA sequencing. Although the ND5 gene fragment had minimal intraspecific variation, eleven sequence types were detected in the ND2 gene. Each sequence type differed in relative frequency between and among the lake trout populations sampled. <p>One particular southern lake trout population, Crean Lake, had markedly different genetic composition in comparison to other lakes in the region. In the 1950s and 1960s, Crean Lake was stocked with lake trout from neighbouring Wassegam Lake in an attempt to increase population numbers. The sequence types of Crean Lake trout and their relative frequencies were dramatically different to those in Wassegam Lake. This suggests that the stocked fish may have been unsuccessful in their establishment/reproduction within Crean Lake. Lake trout from this lake also contained the highest frequency (44%) of rare ND2 sequence type B. Sequence type B was only detected in one other lake (La Ronge), at a very low frequency. <p>The mutational changes in the eleven ND2 mitochondrial DNA sequence types represented three different amino acid sequence types. Substitutions of Threonine and Isoleucine occurred, resulting in two polar amino acids with much different hydropathy indexes. This may affect the tertiary structure of the protein, possibly indicating functional differences. Functionally different proteins may be exhibiting characteristics that allow lake trout to flourish in their environment. <p>The fragments of both the ND2 and ND5 genes proved to be valuable for phylogenetic analyses within the Salmonidae. The genetic markers established in the present study provide the basis for future work on population genetics of lake trout. It would be advantageous to broaden the area of study in order to compare the genetic diversity found within the study area to other regions of Canada. This would determine whether the genetic diversity detected in this study is significantly greater than in other populations at a national scale. Management strategies should ultimately attempt to conserve the genetic diversity found within the lake trout populations of north central Saskatchewan.

I have done a follow up study of the restoration of two rivers, Röälven and Grundan, in order to evaluate the effects of the restoration on the endemic population of trout. Both rivers have been used for timber floating during many years throughout the 20th century, and because of this, had all obstacles such as rocks and wood parts removed. In 2004-2005 both rivers were restored, and rocks and wood were put back into the rivers. Spawning grounds were created and boulder dams were constructed to promote the streaming water. The result showed that the trout population of both rivers increased after the restoration, but also that the trout population of Röälven increased more than that of Grundan. My conclusion is that the way the restoration is of a river contributes to the result.