Highlights

• Larval Snapper were positively affected by projected end of century temperature and pCO₂ from fertilization to 16 days post-hatching.

• Elevated temperature increased the size of larvae, however high pCO₂ had no effect.

• High pCO₂ significantly increased survival at 16 days post-hatch, but elevated temperature had no effect.

• Some species and populations of marine fish exhibit positive effects from projected environmental change.

Abstract

Rising water temperature and increased uptake of CO₂ by the ocean are predicted to have widespread impacts on marine species. However, the effects are likely to vary, depending on a species’ sensitivity and the geographical location of the population. Here, we investigated the potential effects of elevated temperature and pCO₂ on larval growth and survival in a New Zealand population of the Australasian snapper, Chrysophyrs auratus. Eggs and larvae were reared in a fully cross-factored experiment (18 °C and 22 °C/pCO₂ 440 and 1040 μatm) to 16 days post hatch (dph). Morphologies at 1 dph and 16 dph were significantly affected by temperature, but not CO₂. At 1dph, larvae at 22 °C were longer (7%) and had larger muscle depth at vent (14%), but had reduced yolk (65%) and oil globule size (16%). Reduced yolk reserves in recently hatched larvae suggests higher metabolic demands in warmer water. At 16 dph, larvae at elevated temperature were longer (12%) and muscle depth at vent was larger (64%). Conversely, survival was primarily affected by CO₂ rather than temperature. Survivorship at 1 dph and 16 dph was 24% and 54% higher, respectively, under elevated CO₂ compared with ambient conditions. Elevated temperature increased survival (24%) at 1 dph, but not at 16 dph. These results suggest that projected climate change scenarios may have an overall positive effect on early life history growth and survival in this population of C. auratus. This could benefit recruitment success, but needs to be weighed against negative effects of elevated CO₂ on metabolic rates and swimming performance observed in other studies on the same population.View full text

This article appeared on the Marine Environmental Research website at https://www.sciencedirect.com/science/article/abs/pii/S0141113620301719