This study empirically analyzed the factors contributing to the profitability decline of large purse-seine fishery enterprises in Korea. The main findings are as follows. First, both the rate of change in fleet-average catch and the rate of change in fish prices had a statistically significant positive effect on the rate of change in fishing revenue. In addition, the rate of change in fishing revenue significantly affected profit rate whereas the rate of change in fishing costs did not show statistical significance. These results suggest that enhancing fleet-average catch, rather than reducing costs, may be a more effective strategy for improving the profitability of large purse-seine fisheries. Seond, factors related to fishing effort and labor productivity were not statistically significant in explaining variations in total catch. Likewise, the implementation of the mackerel Total Allowable Catch (TAC) system in 1999 and the reduction of fishing areas within Japan’s EEZ following the breakdown of Korea – Japan fisheries negotiations in 2016 did not have significant effects on catch levels. In contrast, a reduction in the number of fleets due to the fishing fleet buyback program had a significant positive effect on catch volume. This implies that it can lead to long-term structural improvements by increasing average catch per fleet through fleet downsizing although he fishing fleet buyback program, may temporarily reduce total catch. Third, chub mackerel landing volume had a significant negative effect whereas import volume had a significant positive effect on landing prices. This unexpected result may be attributed to consumer preferences for specific fish sizes, quality-based market segmentation, or supply-demand imbalances across domestic and international distribution channels. Further research is therefore required to clarify these structural dynamics.