Model-based assessment of climate change impacts on the distribution of northern pike, Esox lucius as an important edible species in the southern Caspian Sea basin in Iran

The climate system is changing at an unprecedented rate in the world. Climate change is having significant impacts on freshwater ecosystems and the fish species that inhabit them. The main purpose of this studywas forecasting the distribution of northern pike, Esoxluciusin the Caspian Sea basin under two optimistic (RCP 2.6) and pessimistic (RCP 8.5) scenarios of 2050 and 2080 by the MaxEnt model in R software. Five environmental variables including, annual mean temperature, temperature annual range, annual precipitation, flow accumulation, and slope were used for the modeling.The obtained results demonstrated that the performance of the model in predicting species distribution was "excellent"(0.977) based on the AUC (Area Under the Curve) criterion.Moreover, the results indicate that the distribution range of northern pike is likely to be reduced by 2050 and 2080 under the both optimistic and pessimistic climate change scenarios. In conclusion, the decreasing distribution of this fish, which is a commercially important and interesting species in sport fishing, poses a serious threat to food security and livelihoods. Therefore, policy makers should pay more attention to conservation and stock management of this species in the future.