Elevated Embryonic Temperature Has Persistent Adverse Effects on Zebrafish Swimming Capacity

In recent years, global warming of anthropogenic origin and its impacts on biodiversity have increasingly gained public awareness. Here, we demonstrate that embryonic temperature can have persistent and crucial effects on zebrafish swimming capacity and cardiac shape. Three different embryonic temperature treatments (TE = 24, 28 or 32 °C) were applied to zebrafish embryos until hatching. Fish were then raised in common conditions (28 °C) until adulthood. Ventricle roundness was found to increase significantly with a rise in TE in juvenile (10% increase) and male (8% increase), but not female fish. TE and sex significantly affected zebrafish swimming performance. Juveniles, males and females raised in cold (24 °C) presented significantly greater swimming capacity than those raised at 28 and 32 °C TE. Our results represent a direct link between the physical capacity of adult fish and embryonic temperature fluctuations that add to the emerging rationale of the potential climate change scenarios on wild fish populations.