한국 연안어업의 실태와 생태계 기반 자원평가

Abstract

Coastal fisheries in Korean waters have highly complexity with a variety of fishing gears, and scale of those fisheries is smaller than that of offshore fisheries. In many cases, vessels operating in the coastal waters tend to commit an illegal fishing, and it causes fishing effort being put overly into those area. In addition, ecosystem of main fishing ground in the coastal waters has been accelerated pollution by aquaculture industry and reclamation activities. As a result, important spawning and nursery grounds for many species of fish has been destroyed. The catch of coastal fisheries accounted for 25.8% of the total catch of Korean fisheries, and the number of fishing vessels involved in coastal fisheries accounted for 94% of the total number of fishing vessels of Korean fisheries. The number of species caught by coastal fisheries is known as about 116, but only 35 species, which accounted for 30% among them, have been examined for stock assessment. Even the assessment on 27 species of those 35 species has been conducted without understanding their biomass levels. To date, stock assessment could not provide sufficient scientific knowledge for coastal fisheries resources, thus it makes difficult to conduct proper stock management. Typical approach of stock assessment used for Korean fisheries is based on single-species models, so it could not provide some important analysis such as biodiversity, habitat status of target species and socio-economic factors. Therefore, it is urgently required to conduct ecosystem-based fisheries assessment (EBFA) for proper stock management. The pragmatic ecosystem-based approach was developed for the assessment of fisheries resources in Korean waters by Zhang et al. (2009; 2010) and a two-tier analytical method was employed. Tier 1 was designed for situations where sufficient information is available to allow for a quantitative evaluation of the status of the system, while tier 2 was designed for situations where available information necessitated a semi-quantitative or qualitative assessment. In general, it is desirable to provide management plan in accordance with the results obtained by the tier 1 of EBFA, which is the quantitative evaluation. However, scientific information on coastal fisheries of Korea is insufficient for the quantitative evaluation, so it is considered that the qualitative assessment with tier 2 of EBFA would be a realistic way in this level. Before conducting the EBFA with tier 2, each 1 species from the East, West and South Sea (total 3 species) were selected and examined their risk scores estimated by the tier 1 and tier 2 to verify suitability of the result of tier 2 which is less objective than tier 1, as comparing both results. Using various statistical tests (i.e. Wilcoxon test, False test and ANCOVA test), suitability on the risk scores by the tier 2 was examined. Through this, it was shown that the risk scores by the tier 2 are generally similar with those of tier 1, and it is considered that the EBFA by the tier 2 is suitable. Thus, EBFA by the tier 2 were conducted on major 3 coastal regions and 7 coastal fisheries in Korean waters. As for the species risk index (SRI), common squid caught by coastal gillnet in the Uljin region had the highest risk. As for the fisheries risk index (FRI), coastal gillnet in the Uljin coastal waters and coastal trap in the Deukryang Bay had the highest risk. As for the ecosystem risk index (ERI), it showed the highest risk in the Deukryang Bay. For the common squid which had the highest SRI, resources management strategies must be established such as catch prohibition of length and period with TAC. For the coastal gillnet in the Uljin region which had the highest FRI, it is judged to need management plans for conserving biodiversity as reducing the catch of non-target species and discards. Also to protect existing habitat, illegal fishery should be prohibited, and fishing gears should be designed in the environmental-friendly way considering when fishing gears lost. Notwithstanding various fisheries resources management were established for conserving main species, biomass of those species still remains in the low level and not to be able to recover its status. It is because that current stock assessment for Korean fisheries is based on a single species or a population. So it is judged that ecosystem-based fisheries assessment would be conducted to improve the quality of stock assessment, and then new management plan considering ecosystem would be established. To conduct EBFA, establishment of database of various input data related to ecosystem information should be precede. For that, data should be collected under the data collecting bodies, and comprehensive data management system being able to control all collected data should be developed. The roadmap for EBFA was suggested in this study. According to the roadmap, EBFA by the tier 2 should be conducted on the coastal fisheries. Through improving the quality of scientific data and establishing tier 2 EBFA system, EBFA by the tier 1 should be conducted in the next step. Based on these results, ecosystem-based fisheries management plan should be established combining with current fisheries management strategies (TAC etc.) properly.