Putative neural and endocrine control of thermal acclimation in fish.

Fishes can acclimate to a range of temperatures. However, the signalling factors controlling thermal acclimation are not well understood. Here, in two experiments, we examined the putative roles of plasma-borne factors (e.

No oxygen limitation of upper thermal tolerance in zebrafish regardless of acclimation temperature.

Understanding the physiological mechanisms that limit the upper thermal tolerance of ectothermic animals during acute warming, particularly the role of tissue oxygen supply, is a key area of interest. Studies manipulating water oxygen levels show mixed results, suggesting that the effect of oxygen availability on upper thermal limits is species and context-dependent. Given the importance of thermal acclimation in modulating acute thermal limits, we investigated whether thermal acclimation impacts the oxygen dependence of Critical Thermal Maximum (CT) in adult zebrafish (Danio rerio).

Dynamics of thermal tolerance plasticity across fish species and life stages.

Climate warming with associated heat waves presents a concerning challenge for ectotherms such as fishes. During heatwaves, the ability to rapidly acclimate can be crucial for survival. However, surprisingly little is known about how different species and life stages vary in their acclimation dynamics, including the magnitude of change in thermal tolerance through acclimation (i.

Global change and premature hatching of aquatic embryos.

Anthropogenically induced changes to the natural world are increasingly exposing organisms to stimuli and stress beyond that to which they are adapted. In aquatic systems, it is thought that certain life stages are more vulnerable than others, with embryos being flagged as highly susceptible to environmental stressors. Interestingly, evidence from across a wide range of taxa suggests that aquatic embryos can hatch prematurely, potentially as an adaptive response to external stressors, despite the potential for individual costs linked with underdeveloped behavioural and/or physiological functions.

A novel method for measuring acute thermal tolerance in fish embryos.

Aquatic ectotherms are vulnerable to thermal stress, with embryos predicted to be more sensitive than juveniles and adults. When examining the vulnerability of species and life stages to warming, comparable methodology must be used to obtain robust conclusions. Critical thermal methodology is commonly used to characterize acute thermal tolerances in fishes, with critical thermal maximum (CT) referring to the acute upper thermal tolerance limit.