Ecosystem-based fisheries risk assessment and forecasting considering a spatio-temporal component in Korean waters

Integrated fisheries risk analysis method for ecosystems (IFRAME) was originally developed to accomplish the goals of an ecosystem approach to fisheries (EAF) to overcome the limitations of the single-species approach. This approach performs ecosystem-based fisheries assessment, forecasting, and management. However, this IFRAME approach does not explain spatial variations in ecosystem components. Although this approach has a number of advantages in mitigating the risks associated with developing macroscopic management measures, its limitation is apparent when microscopic management measures that reflect the spatial features of the species or the fisheries within the ecosystem are required. In this study, the IFRAME was extended to assess and forecast ecosystem dynamics and risk indices in a spatio-temporal context. The distribution of biomass and changes in risk of chub mackerel were predicted using the extended IFRAME, based on scenarios considering changes in climate and variations in fishing mortality. A total of 87% of chub mackerel resources were distributed in the East China Sea in 2019, but they are expected to rise northward due to the rise of the average sea surface water temperature (SST) as per the RCP4.5 and RCP8.5 IPCC scenarios. Based on these scenarios, a major fishing ground was predicted to form around the Yellow Sea in 2069. The species risk index (SRI) of mackerel in 2069 showed relatively low in the East and Yellow Seas, but as climate change continues, the risks in the East China Sea increased. The forecasting results can be used in the management component of IFRAME to assess alternative harvest strategies and tactics in the rapidly changing marine ecosystems. Since food web relationships and water temperature scenarios were only considered as input data for the Ecospace module used in the prediction of mackerel biomass distribution, more quantitative spatial information should be incorporated in the analysis to better explain the complex nature of the marine ecosystems. In conclusion, based on the spatio-temporal IFRAME approach, it could be possible to establish a proper fisheries management plan by incorporating spatial variations in the ecosystem for sustainable fisheries.