The method of extracting effective net length of hairy shrimp net based on ship position data

Abstract

The invention relates to a method for extracting the effective net length of a shrimp net based on ship position data. The jenks optimal natural fracture method is used to determine the speed thresholds of anchoring nets, waiting for catches or resting, lifting nets to catch fishes, and fast sailing states. SQL statements are used to extract point sets of fishing boats in anchoring and netting states, and then DBSCAN clustering is used. The algorithm extracts the network order of the set of anchored network points; based on the latitude and longitude information, the haversine formula is used to calculate the actual network deployment distance of the network order; combined with the characteristics of the net gear of the hairy shrimp net, the distance generated by all the net equipment under the deployment and its effective network distribution The correlation between the distance of the network length is used to calculate the actual effective network length of the network order. The invention can improve the accuracy of extracting the effective net lengths of different net times of hairy shrimp nets, and provide higher-precision method support for improving the quantification of fishing effort.

Description

technical field [0001] The invention belongs to the technical field of application of fishing boat position data, and in particular relates to a method for extracting effective net lengths of hairy shrimp nets based on ship position data. Background technique [0002] As the shrimp resources are facing a severe situation of decline, the fishing quota system has become an important guarantee for the sustainable development of the shrimp resources, and the calculation of fishing effort has become the key to the deep implementation of the fishing quota system. Vessel Monitoring System (VMS, Vessel Monitoring System) is a system that obtains vessel position data through satellites, and can provide positioning time, longitude and latitude information of fishing vessel position, speed and course information. Based on technologies such as the automatic ship identification system and the Beidou satellite ship position monitoring system, my country has initially realized the contact ...

AI Technical Summary

Problems solved by technology

However, although the net gear for hairy shrimp belongs to the type of stretching net, its structure is obviously different from other stretching nets. Its bycatch rate is low and its selectivity for hairy shrimp is extremely high. It is the exclusive net gear for fishing of hairy shrimp.

In addition, the effective length of nets for different nets will change with the actual production and fishing conditions, time and weather, sea environment and other conditions. significantly larger than

Images