To assess potential impacts of effluents from Key Lake and McClean Lake uranium operations on freshwater systems, morphometric (weight, length, condition factor) and biochemical (total body lipids and triglycerides, liver triglycerides, muscle protein, muscle RNA/DNA ratio) measures of growth and bioenergetics were determined in young-of-the-year (YOY) fishes collected in fall and spring. It was predicted that fishes exposed to mining and milling effluents would be in poorer condition relative to fishes from reference sites and that fishes would be depleted in lipids and triglycerides in the spring compared to the previous fall following a northern winter. Various total body lipid and triglyceride measurement methods were initially compared and validated. <p>Lakes receiving effluent at Key Lake (in operation > 20 years) were higher in metals, ions and ammonia compared to exposure sites at McClean Lake (in operation < 10 years). At Key Lake, there were site and season differences in total body lipids and triglycerides in YOY northern pike (<i>Esox lucius</i>) and burbot (Lota lota), with fishes being fattier at exposure sites compared to fishes at the reference site, and fish being fattier in spring relative to fall. A local prey item, spottail shiners (<i>Notropis hudsonius</i>), from an exposure lake were higher in triglycerides compared to shiners from a reference site, suggesting an indirect effect of uranium operation effluent on pike and burbot bioenergetics via food web enrichment. At McClean Lake, there were site and season increases in lipids and triglycerides in burbot from the exposure site, however there were no site differences in any morphometric or biochemical endpoint for northern pike. Slimy sculpin (<i>Cottus cognatus</i>) were the only species with lower triglyceride content in the spring following winter. <p>Overall, biochemical measures of growth (muscle protein, muscle RNA/DNA ratio) did not vary with effluent exposure at either uranium operation. Lipids and triglycerides were useful biochemical endpoints that frequently detected site and season differences in fish condition that were not noted with morphometric measures. Site and season differences in fish lipids and triglycerides at sites receiving mining and milling effluents revealed an impact of the uranium operations on indigenous YOY fish condition.

To assess potential impacts of effluents from Key Lake and McClean Lake uranium operations on freshwater systems, morphometric (weight, length, condition factor) and biochemical (total body lipids and triglycerides, liver triglycerides, muscle protein, muscle RNA/DNA ratio) measures of growth and bioenergetics were determined in young-of-the-year (YOY) fishes collected in fall and spring. It was predicted that fishes exposed to mining and milling effluents would be in poorer condition relative to fishes from reference sites and that fishes would be depleted in lipids and triglycerides in the spring compared to the previous fall following a northern winter. Various total body lipid and triglyceride measurement methods were initially compared and validated. <p>Lakes receiving effluent at Key Lake (in operation > 20 years) were higher in metals, ions and ammonia compared to exposure sites at McClean Lake (in operation < 10 years). At Key Lake, there were site and season differences in total body lipids and triglycerides in YOY northern pike (<i>Esox lucius</i>) and burbot (Lota lota), with fishes being fattier at exposure sites compared to fishes at the reference site, and fish being fattier in spring relative to fall. A local prey item, spottail shiners (<i>Notropis hudsonius</i>), from an exposure lake were higher in triglycerides compared to shiners from a reference site, suggesting an indirect effect of uranium operation effluent on pike and burbot bioenergetics via food web enrichment. At McClean Lake, there were site and season increases in lipids and triglycerides in burbot from the exposure site, however there were no site differences in any morphometric or biochemical endpoint for northern pike. Slimy sculpin (<i>Cottus cognatus</i>) were the only species with lower triglyceride content in the spring following winter. <p>Overall, biochemical measures of growth (muscle protein, muscle RNA/DNA ratio) did not vary with effluent exposure at either uranium operation. Lipids and triglycerides were useful biochemical endpoints that frequently detected site and season differences in fish condition that were not noted with morphometric measures. Site and season differences in fish lipids and triglycerides at sites receiving mining and milling effluents revealed an impact of the uranium operations on indigenous YOY fish condition.

<p>Human actions and the resultant global warming are leading to considerable environmental changes that are negatively impacting marine ecosystems and their biodiversity. Luidia clathrata, a starfish species, is essential to the marine ecosystem, and understanding its sensitivity to stressors can help predict its future adaptations and role in the reef ecosystem. The study involved subjecting L. clathrata to thermal stress by incrementally raising the temperature by 1°C each day for a period of seven days. Physiological responses were evaluated on two separate occasions: day 1, which corresponded to the acute stress response, and day 7, which corresponded to the chronic stress response. The results showed a minor increase in phagocytic activity during acute thermal stress, but a significant decrease during chronic exposure. Although there was a slight decrease in total coelomic plasma protein during acute thermal stress, it significantly increased during post-chronic exposure. The amputated starfish avoided using the injured arm when righting themselves, indicating the development of neurosensory potential. Total cell count increased slightly in all stressed groups during acute stress but decreased after prolonged exposure to stressors. The mortality rate of the temperature-stressed groups was 33%, indicating that prolonged exposure to temperatures exceeding expected future temperatures could be harmful to L. clathrata. To support the hypothesis at the molecular level, RNA/DNA ratios and Heat shock protein gene 90, a molecular marker for cellular stress, were studied. Although no significant differences were observed in transcriptomic level, the temperature-stressed group showed slightly upregulated hsp90 gene expression. The findings indicate that L. clathrata responds to stress similarly to vertebrates, highlighting the potential impact of climate change on marine ecosystems. This study provides a baseline for comprehending the stress response of starfish, and further research is recommended with a larger sample size and over a more extended period. It is interesting to note that the gonad and body wall extracts of starfish exhibit significant inhibitory activity against various tested pathogens. The findings suggest that starfish extracts may have potential medicinal uses as antimicrobial agents. However further research is needed to understand the mechanisms of action behind these inhibitory activities and to identify the specific compounds responsible for them.</p>