어업 평가와 예측을 위한 시공간적 IFRAME 연구

Abstract

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. It incorporates ecosystem models such as the ecosystem-based fisheries assessment approach (EBFA), which is an ecosystem risk analysis tool, and the EwE, which is a static and dynamic ecosystem modeling tool. However, this IFRAME approach does not explain spatial variations of ecosystem components. Although this approach has a number of advantages in mitigating the risks associated with the ecosystems and 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 extended IFRAME has two more components than the original approach. First, a spatial component was added to explain the risk indices by the sea block unit in the EBFA. Second, Ecospace, a spatial and temporal dynamic module in EwE model was incorporated in the forecasting process of the IFRAME. Using the extended spatio-temporal IFRAME, the fishery risk of the ecosystem of the East China Sea in Korea was assessed. The ecosystem risk index (ERI) in the East China Sea for 2018 was estimated to be 1.32, which has increased by 21% compared to 2008. The extended IFRAME enabled an ecological risk assessment for each sea block. For example, the ERI for the Jeju and Tongyeong area for 2018 was highly estimated to be 2.20 and 1.93, respectively. In this situation, this approach could be useful to be able to set proper management measures that focus on those sea blocks with high risks, making use of the results obtained from each sea block. For more scientific spatial assessment, survey and research plans for spatial and temporal ecosystem-based assessment should be established and supplemented. The distribution of biomass and changes in risk of chub mackerel were predicted using the extended IFRAME, based on scenarios considering changes in climate changes and variations in fishing mortality. A total of 87% of chub mackerel resources were distributed in the East China Sea in 2018, 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 2068. The species risk index (SRI) of mackerel in 2068 showed relatively low in the East and Yellow Seas, but as climate change continues, the risks in the East China Sea were getting higher. Results of the forecasting can be used in the management component of IFRAME to assess alternative harvest strategies and tactics in the rapidly changing marine ecosystems. Since foodweb relationships of the ecosystem 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 in order to better explain the complex nature of 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.