Accurate catch data are essential for effective fisheries management. This study reconstructs the historical recreational catch of hairtail (Trichiurus lepturus) in Korean waters by incorporating unreported catches to improve stock assessment accuracy. Using a Bayesian state-space surplus production model, we conducted a multi-fishery stock assessment by integrating abundance indices from eight major fisheries. The multigear mean standardization (MGMS) method was applied to derive standardized CPUE indices for each fishery, providing a more comprehensive evaluation of stock trends. The results indicate that excluding recreational catches and multiple CPUE indices may lead to biased stock assessments of hairtail in Korean waters. Models using an integrated CPUE index (SMSC) yielded higher MSY and biomass estimates, suggesting a more optimistic stock condition, whereas fishery-specific CPUE models (MSC) provided more precautionary estimates. The Kobe plot analysis indicates recent stock recovery, but continued monitoring and adaptive management are required to ensure long-term sustainability. This study highlights the importance of integrating recreational catch data and multi-fishery approaches in stock assessments, particularly under data-limited conditions, to enhance resource management and policy decision-making.

The standardization of catch per unit effort (CPUE) is essential for accurate stock assessment in fisheries management. This study focuses on CPUE standardization for red snow crab (Chionoecetes japonicus) in South Korea, incorporating both spatiotemporal and socioeconomic factors into a generalized additive model (GAM) framework. Using fishery-dependent data from 2009 to 2023, we analyzed the influence of variables such as the proportion of live catch, oil prices, global export prices, and the COVID-19 pandemic on CPUE trends. To quantify the contribution of each variable, a stepwise exclusion analysis was conducted. The results show that excluding socioeconomic variables leads to a more stable CPUE trajectory, indicating that nominal CPUE fluctuations are partially driven by economic conditions rather than changes in biological abundance. These findings highlight the importance of accounting for external drivers, particularly socioeconomic factors when standardizing CPUE. By doing so, the year effect extracted from the model can more accurately reflect relative stock abundance. The approach presented here offers a practical solution for improving CPUE estimates in data-limited fisheries and supports adaptive, evidence-based fisheries management.

Ocean warming driven by climate change is accelerating globally, with Korean waters showing faster sea surface temperature (SST) increases than the global average, posing substantial threats to the fisheries sector. Seaweed, which accounts for approximately 76% of total aquaculture production, is highly sensitive to temperature fluctuations and vulnerable to climate impacts. This study assessed the impacts of climate change on three types of major cultivated seaweed in Korea (kelp, sea mustard, laver) by estimating damage probabilities specific to species and production regions under four SSP scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) across three periods (2030, 2050, 2100). These probabilities were combined with recent five-year average production data (2019 2023) to estimate economic losses. The results revealed pronounced differences in damage probabilities and economic losses by species and production region. Specifically, kelp consistently exhibited damage probabilities under all scenarios, and aquaculture in its primary production area, Jeollanam-do, was projected to become increasingly difficult. In contrast, laver and sea mustard were exposed to risks but showed greater potential for continued cultivation. Notably, although laver exhibited lower damage probabilities than kelp, its higher unit value resulted in the largest projected economic losses among the three species. These findings provide a critical basis for national and regional governments to design adaptive strategies that strengthen the resilience and sustainability of seaweed aquaculture under climate change.