| In the past 15 years, China tuna purse seine fishery developed rapidly. Fishery enterprises continuously input the resources to expand the scale of production, which received good economic benefit. At present the output of Chinese tuna purse seine fleet accounted for 5.6% of the total purse seine fishery output in the Western and Central Pacific Ocean. However, in recent years, as the results of the declining of Skipjack tuna prices in the international market, the rising of catching operation cost and more strict management requirements put forward by the tuna fisheries management organizations on purse seine vessel operation, China tuna purse seine enterprise are facing severely adverse situation and concerning the measures to improve offshore production operations and the vessel’s fishing efficiency. This article study CNFC(China National Fisheries Corp Ltd)’s offshore operation characteristics in recent three years, analyzing the seasonal variation law of fishing ground focus and the influence of the marine environment factors on the distribution of fishing ground. The marine environmental data are directly collected by the CATSAT remote sensing software on board the fishing vessel during fishing operation. Calculating the appropriate interval of marine environment factor that potential fishing grounds distributed, the better use of CATSAT software in searching for fishing grounds and increasing the use ratio of fishing days bought according to VDS(vessel day scheme) and reducing the fuel costs on fish searching. The result of this paper is helpful to the raise of fishing efficiency of China’s tuna purse seine fleets,as well as the improvement of the management efficiency of the fishery enterprises concerned.This article is based on my two year working experience on board tuna purse seine vessel "HSIEHFENG 701" of CNFC. The author collected the fishing production data of the fleet from January1 st 2013 to December 30 th 2015, and recorded the CATSAT software’s marine environment data collected by tuna purse seine vessel "HSIEHFENG701" during the year 2014. Firstly, the author counted three years total fleet catch,by statistical variation of yield and analyze fishing yield between different operating modes and the changes of yield ratio, operation characteristics analysis of reclaimed CNFC purse seine fleet, the fleet quarterly yield and CPUE(catch per unit effort) to analyze the temporal and spatial distribution of focus change, analysis of quarterly variation of focus change.Analyzing the change reason and the fishing days of fisheries enterprises VDS days. Analysis the marine environmental factors’ influence on the tuna fishing ground distribution. Running GAM(Generalized additive model) on CPUE and SST(sea surface temperature data) parameters the marine environment factor distribution calculated can help make better use the CATSAT software to analysis the distribution of fishing ground, improving the fishing vessel and the entire fleet’s fishing efficiency, increase the business of enterprise. The main conclusions of this study as follows:(1) By the statistic of 2013-2015 CNFC tuna purse seine fleet’s yield’s construction,set times and changes from different operation ways, considering the FAD operation times policies limiting effect of prolongation in the western and central Pacific Ocean tuna fisheries management organizations, fad of fleet net accounted for the total operating time ratio will continue to decline, although the free school net work times increase in the proportion, but the analysis of different purse seines in the skunk set rate can see fad operation mode, the fishing efficiency is much higher than that of free school. Another analysis of three years fleet fishing fishing species ratio, the Yellow-fin tuna catches showed an overall increasing trend, fishing for Yellow-fin tuna more from free school set.The increasing proportion of Yellow-fin tuna catches also shows that free school activity ratio increased.(2) By analyzing the 2013-2015 CNFC tuna purse seine fleet’s changes of catches monthly, there is a positive correlation between the catch and the number of the vessels active. Because old tuna purse seiner vessels’ performance is relatively backward.The success rate of free school fish set is low. The improvement of catches is depended on the increase the number of fishing operations,which leads to increased fishing vessel fuel consumption, also accelerated the fishing boats use equipment in the process of loss, so old purse seine vessels per two years must return home to repair and maintenance. The ship’s non work timeoccupies a large number of fishing vessels’ effective production time, the operating efficiency of the tuna purse seine fleets decline, affect the enterprise’s operating efficiency.(3) By analyzing the 2013-2015 year CNFC tuna purse seine fleets yield distribution of quarterly changes found in the past three years fleet’s main fishing ground continuously moving eastward. Analysis reasons have a great relationship with EI Nino. In the first two quarter of the year 2013 CNFC fleet’s focus mainly distributed in the western part of Papua New Guinea, and Micronesia. From the third quarter of 2013 to 2015 fleet’s fishing areas transferred to the Middle Eastern countries,include Nauru, the Marshall Islands and Kiribati. Due to the VDS day prices of PNA member countries continue to rise in recent years, the fishing cost has become tuna purse seine fishery enterprise’s main runing cost.Combined with the analysis of fishery change rules can help enterprises rational planning for VDS days, improve business efficiency.(4) By analyzing the 2013-2015’s fishing ground distribution and SST; The SST spatial distribution diagram can be drawn, focus of fishing ground and the change of SST has a close relationship, the distribution of fishing grounds are suitable for sea water temperature interval. In recent years, The Water temperature variation in the western and central Pacific Ocean affected the distribution of tuna resources, make other changes in fisheries, therefore the appropriate fishing ground distribution of SST range to help quickly find fishing ground, improve our country tuna purse seine fishery enterprise fishing fleet operating efficiency has great significance. By running GAM on 2014 CNFC fleet’s tuna purse seine vessel "HSIEHFENG 701" ’ CPUE and the SST data collected by CATSAT remote sensing system. Based on the analysis of calculated parameters, the most suitable SST temperature should be 29.4 to29.5 ℃.(5) In order to improve the fleet’s operation conditions, CNFC should speed up the construction of new ship weed out the old ship, because the new ship can effectively improve the operating efficiency and reduce cost such as fuel and equipment; CNFC should update the ship’s fish detection instrument,such as radar and sonar,as well as add the helicopter, high power boats and other fishing aid equipment. These can help fishing better improve fleet’s free schooloperation ability.(6) In order to improve the company’s purchase of the status of the VDS days, the CNFC should analyze the change of fishing ground focus of climate change effects, the reasonable plan for operation days of purchase quantity; Strengthen the cooperation with the local island, for different countries working days conversion of preferential policies; Through the association of Chinese ocean fishery tuna purse seine working group and coordination group within the company’s VDS days and prices.(7) In order to improve the search ability of the fishing fleet, the CNFC should strengthen the cooperation with scientific research institutions, the study on formation mechanism of tuna fishing center, especially the environmental factors of climate change induced by the change of effect of purse seine fishery change; Strengthen the cooperation with scientific research institutions, the study on formation mechanism of tuna fishing center in particular, the environmental factors of climate change induced by the change of effect of purse seine fishery change; According to data and information provided by the CATSAT system, using the appropriate method and fishing ground focus distribution correlation, analysis for marine environmental factors associated with the interval distribution of fishing ground, helping the vessels better use the CATSAT system to find the fishing ground;Through the organization of training specifically for the CATSAT system, the captain or other crew members to master CATSAT system function and application of the system of information to determine the central fishing ground; CNFC should enhance the fishery information sharing between vessels,helping to improve the fleet’s fishing efficiency. |
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