Effects of sea surface temperature on tuna catch: Evidence from countries in the Eastern Pacific Ocean

Abstract

This paper explores how changes in sea surface temperature (SST) affect tuna catch in countries in the Eastern Pacific Ocean (EPO). We apply a production function approach to establish the relationship between SST and the catch of yellowfin (Thunnus albacares) and skipjack tuna (Katsuwonus pelamis) that use purse seines. We use data for 1° latitude/longitude grids within the exclusive economic zones of countries in the EPO. Catch of yellowfin and skipjack tuna increases with SST in all countries, with high values of catch recorded in the eastern coastal borders. The biggest increase in revenue from yellowfin and skipjack tuna as result on 1 °C increase in SST is for Mexico, while Kiribati had the smallest increase. However, if we adjust the increase in revenue by coastal population, the highest values are for Kiribati and French Polynesia. The higher tuna catch translates to higher government revenue from tuna fishing licenses, and more jobs for tuna fishers and those in the tuna processing industry in the state. However, the reduction on catch of other species may offset the positive effects on tuna catch, and may even result in a negative impact overall. We highlight the importance of conducting research on SST that is specific to species, gear, and location to fully account for the impact of ocean warming.