Effects of temperature on the survival and development of the early life stages of northern pike (

In the context of global change, the aim of this study was to investigate the effects of temperature on the survival rate and various variables (development time, morphometric measures, energy values) for both embryos and post-hatch stages until first food intake of northern pike (Esox lucius). We applied five constant temperatures (8, 10, 12, 14 and 16 °C) and their effects were analyzed during the entire endogenous feeding period at three stages: hatching, emergence and first food intake. Around 80,000 eggs from five females and five males were used. As expected, the development time was three times longer at 8 than at 16 °C. The survival rate of well-formed post-hatch stages at the end of the endogenous feeding period was similar between temperatures: 76% (10 °C), 73% (12 °C), 72% (14 °C), 72% (16 °C), except at 8 °C (70%). Also at 16 °C, post-hatch stages were larger and had the highest energy value when starting feeding exogenously. These results are in accordance with current models that predict an increase of the distribution area of northern pike in France in coming decades associated with climate change projections (1 to 5 °C increase by 2100 for France).