Climate change vulnerability across life stages in fish

Climate change is increasing the frequency and intensity of extreme weather events (e.g., heatwaves).

This is of particular concern for ectotherms (e.g., fish) as their basic physiological functions are strongly influenced by environmental temperature.It has been suggested that some life stages of fish are much more vulnerable to temperature changes than others.

Specifically, the thermal tolerance range of embryos and spawning adults is predicted to be 20°C lower than larvae and immature adults.

If correct, this would mean that climate change is most likely to impact embryos and spawners, and these life stages should be brought to the top of global conservation priorities.

However, this suggestion was drawn from measurements taken at the different life stages using variable methodology that has been criticised for not being directly comparable.

Therefore, a critical question remains: which life stages of fish are most vulnerable to climate warming?To answer this question, I will first measure the thermal tolerance range of these four life stages in seven fish species using critical thermal methodology, including a novel method that I have developed which allows for comparable measurements to be taken across all life stages.

Then I will investigate the physiological mechanisms underlying vulnerability to temperature extremes using metabolic measurements. Finally, I will measure how embryonic and spawning life stages respond to acute warming in the natural environment.