한국 남해 어장의 생태계 기반 자원평가 및 관리방안

Abstract

Fisheries scientists have recently recognized the potential of ecosystem-based fisheries management to improve the sustainability of fisheries resources. Under the depressed condition of many fisheries resources in Korea, this recognition has been expanded and more effort has been taken to improve this approach. Therefore, a comprehensive ecosystem-based fisheries management approach would require to holistically consider ecological interactions of target species with other species, the complex interactions between fishes and their habitat, and the effects of fishing on fish stocks and their ecosystem. Changes in ecosystem risks were evaluated using the ecosystem-based fisheries assessment (EBFA) approach of Zhang et al, (2009) and the comprehensive ecosystem-based fisheries management (EBFM) plan was made for the southern sea of Korea in this study. The risk assessment of the southern sea ecosystem was conducted by establishing ecosystem management objectives and by estimating risk scores (RS) for indicators. To conduct this analysis a number of indicators and their reference points for assessing these risk scores were developed in this study. The number of indicators in the risk analysis was 28 for the quantitative tier 1 analysis and 30 for the qualitative tier 2 analysis. The objective risk index (ORI), species risk index (SRI), fisheries risk index (FRI), and ecosystem risk index (ERI) were calculated from the risk scores. Comparing the past (1988) and the current (2008) status of fisheries resources, management implications were discussed. In this study target fisheries in the southern sea of Korea were selected for the risk analysis including large purse seines, large pair trawls, anchovy drag nets, and inshore traps. Main target species were also selected including chub mackerel, jack mackerel, hairtail, yellow croaker, yellow goose fish, and anchovy. The ecosystem risk index (ERI) of the southern sea of Korea decreased substantially from 1.036 in 1988 to 0.851 in 2008, and the management status indices (MSIs) showed that there was an improvement in the management of fisheries operated in the southern sea of Korea. In order to establish an EBFM system, the approach of EBFA was found out to be an effective assessment tool of fisheries management measures. Based on the EBFA results which detected some indicators with high risks to an ecosystem, it could be possible to establish proper management plan to reduce the high risks. Regarding the indicators with high risks, more specific management strategies and tactics could be developed. In the assessment for the large pair trawl fisheries, some indicators for the sustainability, such as catch per unit effort, length at optimum catch, mature rate, fishing ground size and catch ratios, which had high risks, could be improved by setting specific management tools for them. Also, to reduce risk indices for the habitat quality and biodiversity, the pollution of spawning grounds and incidental catches could be prevented and the appropriate trophic level must be preserved. In the case of socio-economic benefits, considerations on the enhancement of community-based management system and the government support due to shifted or abandoned fisheries and the unemployment could be made for an economically sustainable development of fisheries. The current fisheries management in Korea utilizes various measures and tools for different species and fisheries. However, the current management do not includes the concept of ecosystem-based approach. Fisheries management made at the ecosystem level of understanding can prevent significant and potentially irreversible changes in marine ecosystems caused by fishing. This study demonstrated that the EBFA approach for analyzing fisheries in a marine ecosystem has the complexity and usefulness, which was applied to a southern sea ecosystem in Korea. It is necessary for the Korean fisheries seriously consider to take the ecosystem-based approach to fisheries management, since most major fish stocks have been depleted due to many reasons including overfishing and coastal pollution.