Response of environmental factors to distribution of skipjack tuna purse seine fishery in Western and Central Pacific Ocean during different El Niña events

Skipjack tuna (Katsuwonus pelamis) is widely distributed in the Western and Central Pacific Ocean, and El Niño events have significant impacts on its distribution. Based on the logbook data from mainland of China and the oceanographic environmental data, we applied the Maximum Entropy Model (MaxEnt) to explore the spatial distribution of fishing grounds and the response characteristics of environmental factors in different types of El Niño events. The results show that: 1) The MaxEnt model could predict the distribution of fishing grounds well. 2) The moderate Central Pacific El Niño events were mainly distributed around 160°E in the equatorial Pacific, while the super Eastern Pacific and weak Central Pacific El Niño events were mainly distributed around 170°E. 3) Sea surface temperature (SST), sea temperature at depth of 50 m (T50) and sea surface salinity (SSS) were the key factors affecting the distribution of skipjack tuna. In the moderate Central Pacific El Niño events, SSS had the highest contribution rate, while in the super Eastern Pacific and weak Central Pacific El Niño events, T50 did. 4) The center of gravity of fishing ground along the longitude was mainly distributed between 160°E and 175°W, and the suitable habitat average percentage was different in different El Niño events. The moderate Central Pacific El Niño events was 24%; the super Eastern Pacific El Niño events was 28%; the weak Central Pacific El Niño events was 29%.