This study aims to identify the spatial distribution patterns and influencing factors of chub mackerel(Scomber japonicus) catch across the coastal and offshore waters of South Korea. The analysis incorporates the entire Korean fishing grounds, using g...
This study aims to identify the spatial distribution patterns and influencing factors of chub mackerel(Scomber japonicus) catch across the coastal and offshore waters of South Korea. The analysis incorporates the entire Korean fishing grounds, using grid-level panel data on mackerel catch volumes, environmental variables (chlorophyll-a, dissolved oxygen, salinity, and sea surface temperature), and fishing effort variables (gross tonnage, number of vessels, and fishing days). First, a spatial autocorrelation analysis was conducted to examine spatial clustering and migratory patterns of mackerel catch. Eight spatial weight matrices were constructed based on adjacency and inverse distance, and Global Moran’s I tests confirmed significant positive spatial autocorrelation across all quarters. The Moran’s I results showed that spatial dependence was weakest in the second quarter and strongest in the first and fourth quarters, consistent with Korea’s seasonal mackerel fishing patterns. In addition, the Local Moran’s I analysis revealed dynamic seasonal clustering patterns on the map, which were consistent with the migratory routes of mackerel for spawning and overwintering. Second, the spatial panel analysis revealed that both environmental and fishing effort factors had significant effects on mackerel catch volumes. Among the fishing effort variables, gross tonnage, number of vessels, and fishing days showed high multicollinearity; therefore, a principal component(PC1) summarizing these variables was derived and used in the model. An increase in dissolved oxygen and sea surface temperature was associated with a decrease in catches, whereas salinity exhibited a strong positive effect. Chlorophyll-a was not statistically significant. These findings are consistent with previous studies linking mackerel abundance to marine environmental variability, providing a quantitative basis for predicting catch fluctuations and identifying productive fishing grounds. Rising sea surface temperatures, in particular, may reduce nearshore productivity, underscoring the need for adaptive resource management under climate change. Fishing effort had a strong positive effect, and its indirect impact exceeded its direct effect, reflecting the large-scale operational characteristics of purse-seine fleets. Such pronounced spillover effects suggest that fishing pressure in one area can propagate to adjacent zones. Third, this study applies a two-stage instrumental variable dynamic spatial panel analysis, representing the first application in the fisheries field. To address endogeneity, the model incorporates both the spatial lag of the dependent variable and its one-period autoregressive term, while the instrument set consists of lagged explanatory variables, their spatial lags, and differenced terms as instruments. The temporal autoregressive coefficient(–0.17) indicated that catch levels did not persist in the same grid over time, reflecting the migratory ecology of mackerel. The spatial lag coefficient(0.96) revealed strong interdependence of catches across neighboring grids. Among explanatory variables, sea surface temperature(–0.28) and PC1(0.48) showed consistent effects with those from the spatial panel models, both exhibiting stronger short-run than long-run marginal effects. The findings provide a scientific foundation for Korea’s ongoing fishery resource assessment and management initiatives. Furthermore, as national marine spatial databases continue to advance, this research framework offers a scalable analytical basis for expanding spatial analyses of fishery resources in the future.