Comprehensive Benefit Evaluation Of Marine Ranching Ecosystem In Zhelin Bay

Marine ranching is an important method to restore fishery resources,improve marin ecological environment of the sea,and promote the sustainable development of fishery resources.In this study uses the ecosystem service theory and emergy analysis theory to evaluate the comprehensive benefits of zhelin bay marine ranchig,aiming to establish a comprehensive evaluation model of marine ranching,quantify the changes in comprehensive benefits before and after marine ranching construction,and make up for the lack of comprehensive assessment of marine ranching.Provides the basis for future marine ranching system assessment and scientific planning management.The results of the study are as follows:?1?To evaluate the marine animal carbon storage in Zhelin bay,elemental analysis was used to determine the carbon content before and after ashing of different tissues and organs of different species in the Zhelin bay marine ranching.Before ashes the average carbon concentration of meat,bones?shell?and viscera are 37.72%⁴7.41%,11.23%³4.91%and 27.58%³3.95%,respectively,of which Osteichihyes,Crustacea?shrimp?,Gastropoda and Bivalvia have better carbon fixation ability,but except Cephalopoda,the other species difference is not obvious.After ashes the average carbon content are1.83%⁸.28%,1.90%¹2.54%and 0.62%⁸.29%,respectively,and the carbon fixation ability of Gastropoda is the highest,followed by Bivalvia.In 2013,the carbon storage of marine animals in the marine ranching of Zhelin Bay was about 6.728×10⁴ t in marine ranching of Zhelin Bay in2013,in which 0.155×10⁴ t carbon was removed from the sea by harvests,accounting for 2.31%of the total carbon storage,and about 0.11×10⁴ t carbon was deposited on the seabed,accounting for 1.7%,In addition,about 6.46×10⁴t carbon was stored in the sea and may re-enter the carbon cycle,accounting for 95.98%.Marine animals have a significant role in carbon storage and can effectively increase the carbon sink capacity of the sea.?2?This paper evaluated the ecosystem services of marine ranching in Zhelin Bay based on the theory of ecosystem services.And tries to analyzed the spatial distribution characteristics by ArcGIS.The results show that after the construction of the zhelin bay marine ranching,the values of ecosystem services increased from 586.31 million CNY to673.7 million CNY;and the value of per square kilometer increased from2.56million CNY to 2.95 million CNY.Among them,the value of supply services increased from 384.37 million CNY to 430.79 million CNY,the value of cultural services increased from 145.35 million CNY to 184.4million CNY,and the regulation service value increased from 56.41million CNY to 58.51 million CNY.However,the value structure don't change significantly,it appears that supply service>cultural service>regulation service,and fishery production has always been dominant in the marine ranching of zhelin Bay.The spatial distribution characteristics of different functional areas in Zhelin Bay marine ranching are roughly as follows:before the construction of the marine ranching,the area the value of the supply service units represented cage culture area>seaweed culture area>shellfish farming area>enhancement and release area>artificial reef area;The post-construction supply service represented cage culture area>shellfish farming area>seaweed culture area>artificial reef area>enhancement and release area.However,there was no significant change in the value per unit area of the regulation service,which was generally expressed as seaweed culture area>shellfish arming area>artificial reef area>enhancement and release area>cage culture area.Among them,the seaweed culture area is at a high level both in terms of supply service value and regulation service value,and has an important influence on the marine ranching ecosystem.?3?The emergy value analysis theory was used to evaluate the changes in the emergy values before and after the construction of marine ranching in Zhelin Bay.The difference between the currency-value and the emergy value of the ecosystem service of Zhelin Bay marine ranching was compared.The environmental renewable resources of the marine ranchingin Zhelin Bay are 5.94×10¹⁹sej,the environmental non-renewable resources are 7.08×10²⁰sej,the economic feedback emergy value is increased from 5.25×10¹⁹sej to 1.41×10²⁰sej,and the emergy production is increased from 6.10×10²⁰sej to 6.37×10²⁰sej.The economic output energy value rose from 6.36×10²⁰sej to 8.58×10²⁰sej.The emergy indicators also produced significant changes.The self-sufficiency rate of the emergy dropped slightly from 0.94 to 0.84,the emergy yield ratio dropped significantly from 11.61 to 4.51,the emergy investment rate rose from 0.07 to 0.18,and the environmental load rate was 6.36 decreased to 3.92,the emergy output feedback rate dropped from 12.11 to 6.07,and the sustainable emergy index decreased from 1.83to 1.15.In general,Zhelin Bay marine ranching has a relatively high degree of dependence on the natural environment,relatively low economic input,and a high environmental load rate before the construction of marine ranching.However,after the construction of marine ranching,the environmental load rate has decreased significantly,and the sustainable development indicators are in the medium levels.After the construction of the marine ranching in Zhelin Bay,the emergy value of ecosystem services rose from 5.89×10^20sej to6.28×10²⁰sej,the emergy supply service value decreased slightly from5.82×10²⁰sej to 5.63×10²⁰sej,and the service emergy of regulation decreased slightly from 1.97×10¹⁹sej to 1.92.×10¹⁹sej,the cultural service emergy value rose from 1.60×10²⁰sej to 2.12×10²⁰sej.The composition of ecosystem service emergy value is basically the same as that of currency-value,which is represented as supply service>cultural service>regulation service.