| Marine fishery resources are an important blue granary for human beings.They not only provide abundant animal protein for human beings,but also provide economic,employment and other social welfare for human beings.Therefore,ensuring the sustainable utilization and scientific development of Marine fishery resources is an important issue of common concern for all countries in the world.How to evaluate the sustainable utilization of Marine fishery resources is a basic scientific problem.According to the statistics of the Food and Agriculture Organization of the United Nations,fish provide 20% of the per capita animal protein intake of about 3.2 billion people,while the world marine catches have been declining year by year after reaching the highest value in the mid-1990 s.The continuous decline of marine fishery resources all over the world also implies that marine ecosystems are facing severe tests.With the decline of catches in various sea areas,the Indian Ocean is the only sea area that still maintains the continuous growth of fishing output.In the past 20 years,the maximum growth rate has reached 8%.Therefore,the sustainable utilization and scientific management of fishery resources are highly concerned by the world and scholars.The Indian Ocean is an important pelagic fishery area in China and its sustainable utilization of resources is related to the success or failure of the high-quality development of China’s pelagic fishery.Therefore,the purpose and significance of the research of this topic are: using fishery statistics from the 1950 s to this year and using grey system theory and methods to analyze the current status of the development and utilization of marine fishery resources in different sea areas of the Indian Ocean.Combined with fishery resources economics and sustainable development theory,an evaluation system for sustainable utilization of fishery resources based on catch statistics is constructed,and scientific evaluation is carried out in different sea areas.Based on the blue growth theory,combined with actual fishery development,this paper provides corresponding countermeasures and suggestions for the management of high seas fishery resources in the Indian Ocean,and establishes a scientific governance system for the development of fishery resources in the Indian Ocean.It provides scientific basis for the high quality development of China’s pelagic fishery in the Indian Ocean.The main results of this study are as follows:(1)Evaluation of sustainable utilization of fishery resources in the Indian Ocean based on grey relational analysis.Based on the statistical data of FAO fishery production in the western Indian Ocean and the eastern Indian Ocean from 1980 to 2018,the sustainable utilization level and status of fishery resources were evaluated scientifically by using grey relational analysis.Since 1980,the eastern Indian Ocean and the western Indian Ocean have been steadily increasing in catches.From 1980 to2018,the catch of the eastern Indian Ocean ranged from 2.188 tons to 6.975 tons,with an average of 4.667 million tons.The catch of the top 20 species accounted for only28.95% of the total catch,and that of the Clupeoids nei,Hilsa shad and Indian mackerels accounted for more than 2% of the catch.The western Indian Ocean catches ranged from 1,829.7 tons to 5,538,000 tons,with an average of 3,794,100 tons.The catch of the top 20 species accounted for 53.03 percent of the total catch,more than 2% of the species are Indian oil sardine,skipjack tuna,Yellowfin tuna,croakers,bombay-duck,Indian mackerel,giant tiger prawn and hairtail.According to the grey relational grade evaluation,the grey relational grade of the western Indian Ocean and the eastern Indian Ocean has been above 0.7 in the past 10 years,which is a high-intensity development state.In recent years,the grey relational grade of the western Indian Ocean and the eastern Indian Ocean has been above 0.9,it shows that the resource status is close to full development,and the potential and space for further development are relatively limited.(2)Evaluation of sustainable use of fishery resources in the Eastern and Western Indian Ocean based on the mean trophic level.Based on the statistical data of catches in the East and West Indian Ocean from 1950 to 2018 provided by FAO,and combined with the trophic level(TL)of relevant fish species provided by Fishbase,this paper discussed the changes of mean trophic level(MTL)and Fishing-In-Balance index(FIB)of catch in the East and West Indian Ocean during 69 years,so as to determine the sustainable utilization of fishery resources in the Eastern Indian Ocean.The results showed that the catches in the East Indian Ocean showed a steady increasing trend from1950 to 2018.The catches of Tenualosa ilisha,Clupea pallasi and Rastrelliger kanagurta were the important catch species in the East Indian Ocean from 1950 to 2018,and their cumulative annual yield accounted for more than 10% of the total catch.The variation of MTL can be divided into three stages: from 1950 to 1974,the MTL was high and its value range was 3.39-3.71 with the average of 3.60 ± 0.07,the annual catch showed a steady increase trend,the average annual growth rate was 6.4%;From 1975 to 1999 the annual MTL fluctuated from 3.21 to 3.47 with an average of 3.35 ± 0.08,the annual catch showed a small and steady increase trend,the average annual growth rate was 4.8%;During 2000 to 2018,the annual MTL from 2000 to 2018 was 3.31-3.43,with an average of 3.38 ± 0.03,and the annual catch showed a slow and steady increasing trend,with an average annual growth rate of 1.6%.The mean FIB index of the three stages was 0.59 ± 0.22,0.94 ± 0.14 and 1.25 ± 0.04,respectively.The value of FIB showed a steady increasing trend and the range of annual variation was smaller,which indicated that the community structure in the East Indian Ocean was becoming more and more stable.The degree of development and utilization of fishery resources increased,while the decline in MTL was small,and the Fi B index showed an upward trend,indicating that the increase in fish catches could make up for the decrease of MTL;and when only populations with TL>3.25 were counted,the average MTL values of 1950-1974,1975-1999,and 2000-2018 were 4.16±0.04,4.18±0.04,and 4.19±0.03,respectively,showing a small and stable increase trend.In this study,it is concluded that the eastern Indian Ocean ecosystem has not been destroyed,and the resources of high-trophic species such as tuna still have development potential,but the development potential of low-trophic species such as sardines is limited.The results showed that the catch in the West Indian Ocean showed an increasing trend from 1950 to 2018,and the increase trend could be divided into three stages:1950-1982,1983-2005 and 2006-2018,among which the catch of small sardines was the highest.MTL is falling first rise to stable change trend,according to catches divided according to phases,its average MTL were 3.49±0.14,3.71±0.06 and 3.71±0.03,high trophic level catches(TL > 3.25)MTL were 4.04±0.04,4.09±0.04 and 4.13±0.01,respectively.MTL of high trophic level(TL > 3.25)and total catches the average trophic level of similar change trend(P < 0.001).The FIB index showed an upward trend on the whole,and the mean values of the three stages were 0.0998±0.1659,0.8041±0.1849 and 0.9782±0.0670,respectively.According to the analysis,the early catch was relatively low in the West Indian Ocean from 1950 to 1982,and the MTL and FIB showed a fluctuating decreasing trend with the increase of the catch of low trophic level such as sardines.From 1983 to 2005,with the increase of high trophic level catch,MTL and FIB showed a gradually increasing trend.From 2006 to 2018,MTL and FIB were relatively stable at a high value.In this study,the structure and function of the ecosystem in the Western Indian Ocean are relatively stable,the fishery resources are in good condition,the structure of trophic grade is stable,and the species with high trophic grade have great development potential.(3)Study of contribution rates of catch among fishing countries and regions in the Western and Eastern Indian Ocean based on dominance analysis.Based on the West and East Indian Ocean catch data provided by FAO from 1950 to 2019,the species and catch composition of main fishing parties in the past 70 years were analyzed by Dominance analysis,the contribution rate of the main fishing parties and species to the total catch was compared under the time series.The results showed that the total catch in the east Indian Ocean was on the rise,which could be divided into three periods:1950-1974,1975-1999 and 2000-2019.There were significant differences among the top ten species of cumulative catch in different stages(P<0.01),and the first five species in catch were pelagic fishes with relatively low trophic level in 1975-1999 and 2000-2019,the cumulative catch of Tenualosa Ilisha was the highest,and the contribution rate of Tenualosa ilisha,Clupea pallasi,Stolephorus anchovies to the total catch was above 8%.Indonesia,Myanmar,Malaysia,Thailand and other ASEAN member countries are the main fishing parties in the east Indian Ocean coastal states and regions,contributing more than 10% to the total catch.Japan,South Korea and Taiwan province of China are the most productive fishing parties in the non-coastal countries and regions of the Indian Ocean,and contribute more than 10% to the total catch.The results showed that the total catch in the western Indian Ocean was on the rise,which could be divided into three periods: 1950-1982,1983-2005 and 2006-2019.There was no significant difference among the first 10 species and fishing parties in the cumulative catch of each stage(P>0.05),the cumulative catch of Sardinella longiceps was the highest,the contribution rate of skipjack and Yellowfin tuna to total catch was relatively high.India,Pakistan and Iran were the highest in all stages of catch in the coastal states and regions,while Spain,France,Japan and Taiwan Province are the noncoastal countries and regions with the highest catch,which contributed to more than10% to the total catch in the western Indian Ocean at each stage.(4)Prediction model of fisheries catch based on GM(1,N)in the Indian Ocean.Based on the catch data of Indian Ocean from 2000 to 2018,the main catch categories affecting the total catch were analyzed by using the grey system theory and method,and several GM(1,N)models were established and compared.Based on the optimal GM(1,N),the total catch in the Indian Ocean from 2019 to 2025 was predicted.According to the study,the main types that affect the total catch in the Indian Ocean were bottom fish,crustacean,pelagic fish,other marine fish and cephalopod,and their grey correlation degree is above 0.70.The optimal prediction model is GM(1,5)and GM(1,6),the average relative error is 1.83% and 1.90% respectively,and the grey correlation degree is above 0.9.The average relative errors for 2017 and 2018 are 3.78%and 3.42% respectively.The total catch projections for 2019-2020 and 2021-2025 in the Indian Ocean are 11.86-12.9 million tons and 12.27-13.24 million tons,respectively.The main increases in catches are likely to come from pelagic,cephalopod and bottom fish.The study concluded that the growth of the total catch in the Indian Ocean during the 14 th five-year plan period was limited,with a total increase of less than 1 million tons,and that the total catch was basically at the stage of full development.(5)The general situation and countermeasures of my country’s fishery development in the Indian Ocean.Based on the general situation of the major international regional fisheries management organizations in the Indian Ocean,this chapter analyzes the management purpose,the participation of various countries and related management measures,and provides a reference for my country’s international presence in relevant sea areas and fishery distribution rights.The problems existing in the development are proposed,and corresponding solutions are proposed to provide reasonable suggestions for the subsequent development and utilization of fisheries in my country.The results showed that China’s fishery production in the Indian Ocean showed that in addition to tuna longline fishing,my country’s main operating methods in the Indian Ocean are purse seine,netting,cover net and squid fishing.At present,China has the following problems in the development of pelagic fisheries in the Indian Ocean: the management of fishery resources in the high seas is increasingly strict,and higher management standards and requirements are put forward for the development of pelagic fisheries.The fishery resources and output fluctuate frequently,which brings great uncertainty to the stable development of distant-water fisheries.Industrial development is facing greater security risks,the threshold for cooperation is constantly increasing,and fishing vessels operating in some sea areas have greater security risks.Pelagic fishery bases are relatively scattered,and the level of technology,facilities and equipment is not high.The rising production costs further aggravate the survival pressure of distant-water fishing enterprises.In order to promote high-quality development,the following countermeasures and suggestions are put forward: actively participate in international fishery governance,and promote the establishment of a fair and reasonable international fishery governance order.Improve the fishing risk assessment system to ensure the overall stability,safety and control of the industry.Rationally develop fishery resources and promote the sustainable development of the industry.Promote the construction of distant-water fishery bases.Improve equipment capability and R&D level.Deepen bilateral fishery cooperation and promote the transformation and upgrading of transoceanic fisheries. |
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