[U-10] Projection and detection of global environmental change

[U10-04] Global climate change and fisheries resources

★Invited Papers

*Shin-ichi Ito¹ (1.Atmosphere and Ocean Research Institute, The University of Tokyo)

Keywords:global climate change, marine ecosystem, living marine resources

Marine ecosystems have been providing variety of ecosystem services. One of the most important marine ecosystem services is provision of the food. The demands on fish have been increasing for these five decades and fish accounts for about 17 percent of the animal protein consumption by the global population. However, it is well known marine fish populations fluctuate responding to climate variability. The largest population fluctuation has been observed in Peruvian anchovy and it has shown multi-decadal fluctuation with an amplitude in which the maximum catch is more than 80 times of the minimum catch. In many fisheries productive region, fish species alternation has been observed in which dominant fish species alternate with multi-decadal time scale. In the western North Pacific, Japanese sardine, chub mackerel and Japanese anchovy have shown distinctive fish species alternation responding to Pacific Decadal Oscillation (PDO). Several possible mechanisms were proposed for the fish species alternations, but the mechanism is still undetermined. Therefore, elucidation of the mechanism of population fluctuation of living marine resources is an urgent task to sustainably use the resources. In addition to climate variabilities such as PDO, global climate change is directly and indirectly affecting the distribution, survival, and reproduction of many living marine resources. The major climate impact drivers affecting to living marine resources are warming, oligotrophication, deoxygenation, and acidification. However, the responses of living marine resources are regionally dependent and make it difficult to understand due to the complex structure of marine ecosystems. In addition, other anthropogenic influences including fishing pressure and contamination make it difficult to distinguish the effects of global climate change on living marine resources. We must elucidate the response of living marine resources to global climate change by advancing global fisheries production modeling coupling with earth system models together with long term global monitoring of marine ecosystems.