## 1 Introduction
Since fishing logs are difficult to obtain and belong to commercially confidential data, analyzing the behavior of fishing vessels based on AIS data, determining the position status of krill vessels, and identifying and simulating the distribution information of fishing grounds according to the position data of the fishing status have become a new approach to studying the habitats of krill. In recent years, many scholars have applied AIS data, combined with technologies such as the threshold method and deep learning, and successfully achieved high-precision identification of the fishing behavior of fishing vessels, and extracted fishery information such as the fishing locations and fishing efforts of fishing vessels [12; 13; 14; 15]. These achievements provide a new perspective and theoretical basis for the management of fishery resources and ecological protection. Although there have been a few preliminary studies on the method for determining the position status of traditional variable-depth krill trawls and the extraction of fishing ground locations [16], there are still no relevant reports on the position status of pump-suction continuous fishing trawls and the locations of fishing grounds. This has left many research gaps in the accurate identification of the central fishing grounds of krill suitable for the pump-suction trawl fishing gear and the prediction of krill habitats, which is not conducive to the efficient fishing production of krill under the quota management system. Currently, no relevant research has been found on analyzing the habitats of krill based on AIS vessel position data and marine environmental factors. The distribution of krill resources is uneven, and the resources of high-density fishing grounds often concentrate in areas with large marine environmental gradients and are accompanied by significant spatio-temporal changes. Marine environmental factors, such as sea temperature, sea ice, chlorophyll concentration, distance from the shore, salinity, sea surface height, etc., all have an important impact on the habitat distribution of krill [3; 4; 5; 6]. The fishing operations of fishing vessels need to rely on the distribution characteristics of krill to determine suitable fishing areas. Usually, suitable environmental factors often mean a higher abundance of krill resources and a more obvious aggregation of krill, which also attracts fishing vessels to these areas for fishing. Since the pump-suction trawl vessels conduct continuous fishing and do not perform the operations of hauling and setting the net, their towing speed can maintain a relatively stable low speed state, and the vessels mainly aim at fishing according to the position of krill clusters, resulting in large changes in the course during the fishing process. The fishing status in the positions of pump-suction trawl vessels is an important reference basis and data source for analyzing the fishing behavior of these types of vessels and the spatio-temporal positions of krill habitats. Based on this, the fishing duration, operation hotspots, and the position distribution of krill habitats can be extracted. Therefore, in-depth research on the relationship between the fishing location points of fishing vessels and marine environmental factors helps to deeply understand the changing pattern of the abundance of krill resources and provides scientific support for the management and protection of fishery resources.