The purpose of this study is to select a fishing gear deposit marking method for the gear deposit system implemented for gillnet. The fishing gear deposit system was implemented in Korea for the first time in the world in January 2024 for fish trap, and it is scheduled to be expanded to gillnets and buoys by 2026. In this study, an AHP (Analytic Hierarchy Process) survey was conducted with 34 experts. The AHP analysis method was used to calculate the weights of each criterion that influence the selection of the deposit marking method, in order to determine the optimal marking method that considers both qualitative and quantitative criteria. Experts prioritized the label-type marking and preferred the weight-based deposit unit for its ease of application and ability to measure multiple gear widths at once. This study quantitatively reflects the opinions of experts on the selection of the gillnet deposit system. Future research should examine the impact of marking method on fishing performance, durability, and institutional improvements.

This study sought various ways to prevent the occurrence of waste fishing gear and promote the recovery. It is expected that the problem of waste fishing gear can be effectively solved through measures such as strengthening education and publicity, technical measures, establishment of recovery infrastructure, and provision of incentives. In particular, introduction of the waste fishing gear recovery promotion point system gives fishermen practical motivation. It can be an important means of inducing leisure and sustainable fishing activities. In addition, by inducing the participation of private companies, it is expected to promote the recovery and recycling of waste fishing ports and contribute to the protection of the marine environment and fisheries resources. The government or local government should actively review the measures suggested in this study and prepare related laws and policies. In addition, it is necessary to establish a system to induce the participation of various stakeholders and support sustainable fishing activities through public-private cooperation. Through this, we will be able to achieve carbon neutrality goals in the fishing sector in response to climate change. This study suggests an early stage plan, and in future research, it is necessary to evaluate and find and improve practical effects through pilot projects. Moreover, it is necessary to study the management of closed fishing gear and carbon neutrality practice measures at the global level by seeking international cooperation measures. Consequently, more effective and sustainable marine environment and fishery resource protection measures can be prepared.

As discarded fishing gear settles or floats on the seabed, it destroys the spawning and habitat of fisheries resources that causes various safety accidents and adverse effects on the environment, such as generating microplastics and causing ship accidents. In order to solve this problem, this study is intended to present an implementation plan for establishing a fishing gear deposit system in order to use it as basic data for establishing policies for fishing gear management in Korea. In order to successfully implement the fishing gear deposit system, the deposit system must be established in the form of fishing gear completed at the production stage. It was found that the marking of the object should be easy, and that determining an appropriate deposit amount to motivate the return of waste fishing gear and establishing a convenient return procedure for returned waste fishing gear were important factors. In addition, transparent management of unreturned deposits and mandatory use of fishing gear subject to the deposit system for fishermen will be necessary. The role of a specialized organization to manage and operate all of these procedures is also very important. It is necessary to establish a new mandatory provision in the Fisheries Act to require fishermen who directly use fishing gear to use fishing gear with a deposit refund mark, and to ensure the implementation of the deposit system by linking it with the evaluation items of government policy projects. Since the main purpose of the deposit system is to collect discarded fishing gear, a support plan will be necessary in accordance with the purchase project for fishing waste salvaged by local governments in 2020.

This study was conducted to investigate the effects of different water temperatures (8, 11, 14 and 17°C) on growth, survival and hematological parameters of juvenile chum salmon (Oncorhynchus keta) for eight weeks. At the end of the experiment, at 14°C, the final body weights of the O. keta group were the highest compared to the other groups. Also, the O. keta showed a higher tendency in the 14°C group than the 8, 11, and 17°C groups in terms of growth performances, including specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency (FE), weight gain (WG), and condition factor (CF). The survival rate (SR) was 100% at 8 and 11°C groups, 96% at 14°C group and 98% at 17°C group. In the plasma components, the alanine aminotransferase (ALT) was significantly decreased at 17°C group, whereas there was no significant change in the albumin (ALB), total protein (TP), sodium (Na+), potassium (K+) and chloride (Cl-) levels. Among the whole-body composition of salmon, moisture, crude protein, and ash were not significantly affected by water temperature. However, crude lipid in the 8°C group was significantly higher than in other water temperature groups. The results of this study demonstrated that the optimal temperature to stable growth performance for juvenile O. keta was 14°C.

본 연구는 연어(Oncorhynchus keta) 치어의 성장, 생존 및 혈액 성상에 미치는 염분 농도의 영 향을 파악하고자 실시되었다. 실험은 염분 농도 0, 10, 20 및 30‰에서 30일간 실시되었으며 3반복으로 진행되었다. 4주 후 생존율은 0, 10 및 20‰ 실험구에서 87.5% 이상이었으나, 30‰ 실험구는 75%로 유의한 감소를 보였다. 증중율(Weight gain), 일간 성장률(specific growth rate), 사료효율(feed efficiency), 일간 사료섭식량(daily feed intake), 일간 단백질섭취율(daily protein intake), 단백질효율(protein efficiency ratio)은 10‰ 실험구에서 가장 높았다. 혈장성분 중 ALT (alanine aminotransferase)는 10, 20 및 30‰ 실험구가 0‰ 실험구에 비해서 유의한 감소를 보였으나, Na+ (sodium)과 Cl- (chloride)는 유의한 증가를 보였다. 또한, 실험기간 중 TP (total protein)과 K+ (potassium)은 변동을 보이지 않았다. 결론적으로 연어 치어(11~33 g)의 성장과 생존에 적합한 최적의 염분 농도는 10‰로 보이나, 혈액 성상의 영향은 향후 추가적인 연구 가 필요한 것으로 판단된다.