Study On Optimizing The Number Of Monitoring Ships In Marine Fishing Sampling Survey In Zhejiang Province

Fishery production monitoring data and fishery scientific investigation data are two kinds of basic data for carrying out fishery resources assessment and specifying management strategies.Among them,production monitoring data are produced with fishery production activities.They are the key source of information about fishing volume and fishing capacity,and the authenticity and accuracy of their data are very important.Based on the data of the pilot report of marine fishing sampling survey in Zhejiang Province in 2017,this paper makes a multi angle optimization analysis through computer software R and python,takes the target species yield in different months in the original data as the basis of computer simulation,analyzes the changes of optimization indicators under the number of fishing vessels in different samples,and optimizes the simulation results;Taking the operation modes in different areas in the original data as the basis of stratified sampling,taking the output of target species in each operation mode as the basis of computer simulation,this paper analyzes the changes of optimization indexes under the number of fishing vessels in different areas,and optimizes the simulation results;Select the target species in different operation modes,take the species detection rate of the target species as the basis of computer simulation,analyze the changes of optimization indexes under the number of different sample fishing vessels,and optimize the simulation results.The results show that:(1)Based on the data from the sampling survey of marine fishing in Zhejiang Province,through the computer software R3 6.3 the statistical software calculates the yield of target species in different months,and takes the yield of target species in different months in the original data as the basis of computer simulation.The calculation results show that the REE and Rb values of the estimated monthly fishing yield and total yield of each species decrease with the increase of the number of monitoring fishing vessels,and the REE value decreases faster when the number of fishing vessels is less than 110,When it is higher than110,the decrease of REE value slows down and tends to be stable.At the same time,the reduction of REE value when the number of monitoring fishing vessels is increased by 10 is analyzed.When the number of fishing vessels is 70,the reduction of REE estimated value of each research target is less than 5%.At this time,the total number of monitoring fishing vessels is reduced by 73.28%;When the number of fishing vessels is 110,the reduction of REE value is less than 1%,and the number of fishing vessels decreases by58.11%.According to different optimization investigation and research objectives,there are great differences in the optimization results of the number of fishing vessels.(2)Taking the operation modes in different regions in the original data as the basis of stratified sampling for optimization research,the REE mean value of single ship output and total output of each species in each region decreases with the increase of the number of monitoring ships,and the decline slows down when the number of monitoring ships increases to a certain number.At the same time,in the process of monitoring ship optimization,the REE mean value of target species yield and total yield decreased significantly.By analyzing the relationship between the average REE of the yield and total yield of each target species and the number of monitoring ships,the number of monitoring ships in four regions of Zhejiang Province is optimized from 240 to 145.At this time,the number of monitoring ships is reduced by 39.58%,and the average REE of the total yield of each target species is not increased by more than 10%.Different operation modes have different effects on REE value,which can increase the number of fishing vessels with greater impact,ensure the accuracy of monitoring data,reduce the number of fishing vessels with less impact and reduce the monitoring cost.(3)Based on the data obtained from the sampling survey of marine fishing in Zhejiang Province and taking the different operation modes in the original data as the basis of stratified sampling,the species detection rate of the target species is calculated through the computer software python,and the changes of REE and Rb values of the species detection rate under the number of fishing vessels in different samples are analyzed.The final optimization result is 129.Compared with the original number of monitoring vessels,the number of monitoring fishing vessels is optimized by 50.76%.This paper optimizes the number of monitoring fishing vessels in Zhejiang Province in 2017 from different angles.The optimization results from all angles can effectively save the investigation cost and take into account the data quality.This research method has strong operability and can provide reference for other provinces or the whole country to carry out marine fishing sampling survey.At the same time,it is of great significance to improve marine fishing production statistics and grasp the dynamic changes of fishery resources.