## 4 Discussion
### Spatial and Temporal Distribution of Fishing Vessel Operations  
Light purse seine vessels in the Arabian Sea of the Indian Ocean exhibited heightened activity during the first and fourth seasons, with the primary fishing period spanning from late September to May of the following year. This is consistent with the occurrence of the northeast monsoon in the Indian Ocean, indicating continuous operation by mainland China's light purse seine fishing vessels throughout the year in this region. Spatially, the distribution of fishing vessel operations formed a distinct patchy pattern, predominantly close to the Omani EEZ area. The notable areas of high fishing intensity were concentrated in the study area, with the spatial clustering of fishing vessel operations observed at 60\({}^{\circ}\)-68\({}^{\circ}\) E, 15\({}^{\circ}\)-20\({}^{\circ}\) N. The spatial similarity index test results affirm that the spatial information extracted by the three methods closely aligns with the distribution and movement trends of the fishing grounds.  
There is a potential correlation between the center of fishing effort and the ecological and environmental factors in the Arabian Sea. Firstly, ocean temperature is a significant factor influencing the center of fishing effort. The ocean temperature in the Arabian Sea varies significantly with the seasons; in winter, when the water temperature is lower, fishing vessels may migrate to warmer waters, whereas in summer, with rising temperatures, they may move to cooler areas. From January to May 2021, the center of the fishing effort gradually shifted from lower to higher latitudes, and from October to December, it remained at higher latitudes, closely linked to the seasonal temperature changes. In contrast, from January to May 2022, the center moved from higher to lower latitudes, opposite to the pattern in 2021, but the movement from October to December was consistent with 2021, demonstrating the impact of seasonal temperatures on fishing activities. Secondly, ocean productivity also plays a crucial role in influencing the center of fishing effort. Ocean productivity directly affects fish growth and distribution, with the areas of high primary productivity typically attracting more fishing vessels. The abundance of phytoplankton and nutrient supply in the Arabian Sea are significantly influenced by monsoons and ocean currents. The rainfall and nutrients brought by the southwest and northeast monsoons promote changes in ocean productivity, thereby affecting the spatial distribution of fishing effort. A high coefficient of variation (\(Cv>1\)) and a global Moran's I index (Moran's I \(>0\)) indicate that squid fishing activities exhibit significant spatial clustering rather than random distribution, which is highly correlated with the spatial distribution of ocean productivity. Overall, the seasonal and spatial movement of the center of fishing effort partially reflects the significant impact of the ecological and environmental factors in the Arabian Sea on fishing activities.  
The considerable variability observed in the fishing vessel operating spaces across different months indicates substantial seasonal fluctuations in fishery resources within the region. The existing research has focused primarily on analyzing the relationships between resource variations and environmental factors during the fishing season [28]. However, there is a significant gap in the understanding of the migration patterns and routes of key catch species, such as squid and mackerel, in this particular sea area. Current studies have not fully elucidated these migration dynamics. Addressing this gap will require further observations and survey studies. More comprehensive research efforts in the future will contribute to understanding the migratory behavior of major catch species, providing invaluable data for a deeper comprehension of the ecosystems within this sea area.