From a conservation perspective, it is important to identify when sub-lethal temperatures begin to adversely impact an organism. However, it is unclear whether, during acute exposures, sub-lethal cellular thresholds occur at similar temperatures to other physiological or behavioural changes, or at temperatures associated with common physiological endpoints measured in fishes to estimate thermal tolerance. To test this, we estimated temperature preference (15.
View Article and Find Full Text PDFRising carbon dioxide (CO) in aquatic ecosystems due to climate change is a challenge for aquatic ectotherms. We examined whether interindividual variation in behavioural responses to CO could predict how a teleost fish would respond to elevated CO for multiple phenotypic and molecular traits. To this end, we first quantified behavioural responses of individuals exposed to acute elevated CO, and used these to assign individuals as either high or low responders relative to the population mean.
View Article and Find Full Text PDFFreshwater ecosystems and fishes are enormous resources for human uses and biodiversity worldwide. However, anthropogenic climate change and factors such as dams and environmental contaminants threaten these freshwater systems. One way that researchers can address conservation issues in freshwater fishes is integrative non-lethal movement research.
View Article and Find Full Text PDFUnderstanding the resilience of ectotherms to high temperatures is essential because of the influence of climate change on aquatic ecosystems. The ability of species to acclimate to high temperatures may determine whether populations can persist in their native ranges. We examined physiological and molecular responses of juvenile brook trout (Salvelinus fontinalis) to six acclimation temperatures (5, 10, 15, 20, 23 and 25°C) that span the thermal distribution of the species to predict acclimation limits.
View Article and Find Full Text PDFThe upper thermal tolerance of brook trout Salvelinus fontinalis was estimated using critical thermal maxima (CT ) experiments on fish acclimated to temperatures that span the species' thermal range (5-25°C). The CT increased with acclimation temperature but plateaued in fish acclimated to 20, 23 and 25°C. Plasma lactate was highest, and the hepato-somatic index (I ) was lowest at 23 and 25°C, which suggests additional metabolic costs at those acclimation temperatures.
View Article and Find Full Text PDFMost marine teleosts defend blood pH during high CO2 exposure by sustaining elevated levels of HCO3(-) in body fluids. In contrast to the gill, where measures are taken to achieve net base retention, elevated CO2 leads to base loss in the intestine of marine teleosts studied to date. This loss is thought to occur through transport pathways previously demonstrated to be involved with routine osmoregulation in marine teleosts.
View Article and Find Full Text PDFComplex training is characterized by pairing resistance exercise with plyometric exercise to exploit the postactivation potentiation (PAP) phenomenon, thereby promising a better training effect. Studies on PAP as measured by human power performances are equivocal. One issue may be the lack of analyses across multiple sets of paired exercises, a common practice used by athletes.
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