Study On Ecological Effect Evaluation Of Lushun Marine Ranching

Marine ranching is based on the theory of marine ecosystem,in a specific sea area,through artificial reefs,stock enhancement and other measures to build or repair marine species reproduction,growth,baiting or avoiding the enemy required to increase the conservation of fishery resources,improve the ecological environment of the sea,to achieve sustainable exploitation of fishery resources fishing model.In this study,the ecological survey data of the Marine ranching area and the control area in the Lushun Sea area from September 2021 to November 2022 were taken as the research object,and the ecological effects of the construction of Marine ranching area in Lushun were evaluated by analyzing the biodiversity of the Marine ranching area and the control area from the aspects of community structure,dominant species and ecological niche.At the same time,according to the ecological survey data and related literature,the organisms of the Marine ranching ecosystem in Lushun were divided into 20 functional groups,and the Ecopath model of the Marine ranching was constructed to further analyze the current status of the Marine ranching ecosystem in Lushun,and the relationship between the structure and energy flow of the Marine ranching ecosystem was analyzed.It is expected to provide scientific basis for the long-term construction planning of Lushun Marine Ranching.The specific results are as follows:1.According to the four seasons ecological survey data of Lushun Marine ranching area,the Marine ranching area has more abundant species composition and higher catches.In the Marine ranching area,the main organisms found in each season survey are fishes,and the bottom fishes are the main species.Among the three habitat models in the Marine ranching area,the model area with the combination of artificial reef and floating raft had higher catches in all seasons except autumn.2.The dominant species composition of the four seasons in the Marine ranching area was mainly fish except summer.Among them,the Hexagrammos otakii is the absolute dominant species in the Marine ranching area.The dominant species composition in the control area was mainly fish and echinodermata.The biodiversity index of the Marine ranching area was better than that of the control area in four seasons,and the average community diversity index of the combined model of artificial reef and floating raft in the Marine ranching area was higher in spring and autumn.3.According to the results of cluster analysis and NMDS（Non-metric multi-dimensional scaling）analysis,the biomes in the Marine ranching area and the control area can be divided into four groups at the similarity coefficient level of 20%,with the difference is the largest;The biomes of Marine ranching could be divided into five groups at the similarity coefficient level of 34%,with the internal community structure of autumn and winter in the Marine ranching area.According to the analysis results of ABC curve,the biological community in Marine ranching area was less disturbed than that in control area.In the Marine ranching area,the disturbance degree of biological community in four seasons was as follows:summer>Spring>Autumn>Winter.4.The biological niche width of Lushun marine ranching area varied from 0.07 to 5.79,and the largest niche width was Hexagrammos otakii.The niche width of the control area varied from0.15 to 1.73,and Sebastes schlegelii had the largest niche width.The niche overlap value Q of the main fishery organisms in the marine ranching area and the control area were both 0～1.Species utilization resources in the two areas were highly similar,and some major fishery organisms had the phenomenon of inter-species competition,and the competition among major fishery organisms in the control area was even greater.5.The total flow of the Marine ranching ecosystem in Lushun was 29392.41 t·km^-2·a^-1,the total primary production/total respiration（TPP/TR）was 1.16314,the Connectance Index（CI）was0.36,the System Omnivory Index（SOI）was 0.31,and the Finn’s cycling index（FCI）was 11.98.The Finn’s mean path length（MPL）was 3.11,and the Shannon diversity index was 2.03.The trophic levels of each functional group ranged from 1 to 3.89,the first trophic level was detrite,phytoplankton and macroalgae,and the highest trophic level was Sebastes schlegelii.The values of EE ranged from 0.21 to 0.89,with phytoplankton having the highest value and Sebastes schlegelii having the lowest value.The energy conversion efficiency of Lushun Marine ranching ecosystem is 14.43%,which belongs to the high level.6.According to the Ecopath model,the ecological capacity of Sebastes schlegelii is 9.860t/km².The ecological capacity of Hexagrammos otakii is 12.34 t/km².The ecological tolerance of Conger myriaster was 9.05 t/km²;The ecological capacity of Octopus variabilis was 8.74 t/km².The ecological capacity of Charybdis japonica was 9.789 t/km².The ecological capacity of Pagurus ochotensis was 14.71 t/km².At present,the biomass of all economic species has not reached half of the ecological capacity（K/2）.Therefore,attention should be paid to the impact of local fishing activities on economic species,and the protection of marine ranching ecosystem should be strengthened to realize the sustainable use of resources.In this study,it was found that compared with the control area,the biological community in Lushun marine ranching area had more stable structure and higher diversity.The habitat pattern of artificial reef and seaweed raft combination in marine ranching has higher catch quantity and weight and biodiversity.The marine ranching ecosystem in Lushun has a high energy flow and high biodiversity,but the ecosystem maturity is low,and the energy within the whole ecosystem cannot be fully utilized.At this time,the ecosystem is in the early stage of development.