Southward Migration: How Climate Change Alters the Prey Dynamics of Spotted Seal in Western Pacific Ocean

Aim

The Ocean is the major carrier of energy storage of the earth and is greatly affected by climate change and human activities. The spotted seal (Phoca largha) is a national first-class protected species in China and is the only pinniped species that breeds in China waters. This study investigated the impacts of climate change on the distribution of primary prey fish species of spotted seal from 1970 to 2060, and based on the results and conclusions, conservation strategies for spotted seals are proposed.

Location

The Yellow and Bohai Seas, China.

Methods

Three earth system models and the dynamic bioclimate envelope model are used to predict the distribution of the primary prey fish species of spotted seal under two climate scenarios in this study.

Results

The projections show that from 1970 to 2060, the prey fish species of spotted seal shifted southward by 82.06 and 87.91 km under the RCP2.6 and RCP8.5 scenarios, and compared with 1970, the northern limit of primary prey fish species latitudinal distribution shifted northward, the relative abundance increased, and the total maximum catch potential increases under two scenarios (the increment is more obvious under RCP8.5 scenario) in 2060. In addition, the mean temperature of the relative abundance value of the primary prey fish species increases at an average rate of 0.044°C/decade under RCP2.6 scenario and 0.072°C/decade under RCP8.5 scenario.

Main Conclusions

From 1970 to 2060, the primary prey fish species of spotted seal are projected to migrate to lower latitudes, and projections show an expansion of the distribution range of primary prey fish species, an increase in the relative abundance increases in the Bohai Sea and the northern Yellow Sea, a slight increase in the maximum catch potential increases slightly in 2060 compared to 1970, and the mean temperature of the relative abundance increases greatly with the increase of greenhouse gas emissions. According to the results of the study, the conservation of spotted seals should clearly delineate the shoreline at the boundary of the core area, prohibit industrial development and artificial encroachment and build an ecological corridor.