Thermal windows and metabolic performance curves in a developing Antarctic fish

Area of Science:

• Marine Biology
• Ecology
• Physiology

Background:

• Ectotherm physiology is temperature-dependent, varying with thermal history and life stage.
• Adult Antarctic fish display thermal plasticity, but early life stage thermal performance is poorly understood.
• Antarctic ecosystems face warming, necessitating research on species' adaptive capacities.

Purpose of the Study:

• To investigate the effects of acute warming and acclimation on survival and metabolic rate in early dragonfish embryos.
• To characterize the thermal performance curves of Antarctic fish embryos.
• To assess the thermal sensitivity (Q10) and plasticity of embryonic metabolism.

Main Methods:

• Embryos of the dragonfish Gymnodraco acuticeps were subjected to acute warming (-1 to 8°C) and acclimation (2 weeks at -1, 2, or 4°C).
• Survival rates and standard metabolic rates were measured.
• Metabolic performance curves and temperature sensitivity (Q10) were analyzed.

Main Results:

• Embryos exhibited high survival rates even after acute warming to 8°C and acclimation to warmer temperatures.
• Metabolic performance curve height and shape were significantly altered by acclimation at -1°C and further modified by warmer acclimation.
• Temperature sensitivity (Q10) ranged from 2.6 to 3.6, with higher sensitivity in earlier developmental stages.

Conclusions:

• Early-stage Antarctic dragonfish embryos demonstrate remarkable thermal tolerance and plasticity.
• Metabolic performance curves reveal developmental costs under warming, influenced by phenology and seasonal temperature fluctuations.
• Findings provide crucial insights into the resilience of Antarctic marine ectotherms to climate change.