| The ocean fishery resources have reduced seriously because of over-fishing. Our oceanic breeding developed rapidly at the end of 1970s. With the rapid development of marine aquaculture, the influence created by investment and extending the size blindly is becoming far more serious. Breeding diseases are frequent, culture zones and adjacent waters of the ecological environment are polluted and destructed seriously. The mariculture influence upon marine ecosystem has caused general concern in public. Development of marine aquacuture, the influence created by investment and extending the size blindly.Hebei changli waters lying to the westsouth of liaodong bay provide a proper cultural condition for the mariculture, development due to its clean water, weak flow, small wave, high transparency, rich nutrition materials, few ocean disasters and estuary fine sediment beaches. Since the 1980s, raft culture of scallop in maritime, Tidal pond aquaculture, bottom sow aquaculture, factory aquaculture and other forms of Marine aquaculture expand rapidly. The sea size using for breeding has been the leading role of all the sea using.However, with the continual extending of mariculture size, series of ecosystem problems arise, such as water quality deterioration, marine biological Community structure change, biodiversity decrease, destruction of important Speciesl ancelets granted as the country’s second level animals and the drop in production and quality when we make a handsome economic profit. Some main Marine ecosystem is not functioning obviously well including the wetland in seven-mile lagoon and LuanHeKou delta affected by large exploitation. Large and dense raft culture of scallop changed hydrodynamic environment and lowered the marine ability of self-purification and dispersion of pollutants.This paper based on collecting history recources, spot survey, environmental test, distant image processing and data analysis completely and systematicly studied the ways and density of different forms of marine culture on sea eco-surroundings. It puts forward some effective ways to lower marine culture’s influence on eco-environment. it will be of great significance on proper distribution of mariculture industry, improving and protecting marine ecosystem environment and promoting marine culture’s economic and sustainable development.Results of research:(1) Marine culture plays an important role in the ChanLli fishing economy and primarily are raftculture of scallop. In 2009, its total value accounts for 90.9% of all that the marine products created. Its production reaches 90.3% and most of them are seashell weight 97648t accounting for 96%. The total size of marine culture is 44350 Square Kilometers and 93.1% is taken by breeding on sea,6.7% is pond breeding and the rest is factory breeding.(2) Influence of marine-pond culture on typical ecosystem①Influence on seven-mile galloon wetland ecosystem. Through our data analysis by distant image processing, the finding shows that the natural size of seven-mile galloon are gradually reduced and replaced by manmade pool due to humans, high strength development on pool. We may conclude that reclamation breeding cause lagoon peripheral swamps almost disappear in 2009. Take the 1987 as a dividing point, from which our humans begin the pool breeding within a size of 877.6hm2 in 1987 and increase to 1801.84 hm2 2.1 times lager as that in 1987.②Eco-Function of wetland weakened influence on eco-environment of LuanHeKou wetland.in 1980s breeding through shallow cofferdam appeared in LuanHeKou which occupy a great deal of swamp sandy wetland. Size of pond breeding increased from 225.31hm2 in 1987 to 2126.42hm2 in 2009 about 9.45 times. During the 30 years from 1979 to 2009 the size of wetland in LuanHeKou decreased sharply about 2 thirds of the begingings. The wetland takes a trend that it seems backward to land because of the influence created by cofferdam breeding activities. Using the sea water to breed in pool have caused following consequences:firstly,natural wetland decreased and eco-function weaken.secondly, due to the breeding wastes emissions, the near sea areas bearing a heavier burden. Thirdly, diversity of wetland species dropped. Last, the original tide ditch system has been destroyed.(3)Shallow sea raft culture of scallop in maritime ocean-based cultivation environmental impact. Through the analysis of the water environment, nutrient content culture zones are found significantly higher than the culture zones, and transparency, DO, chlorophyll-a, PH value generally lower than the culture zones, mariculture pollution on Marine environment influence mainly happened in breeding mid-late(Aug,Oct) has the hysteresis and accumulating. Breeding sea area affected by inorganic nitrogen pollution is serious, more than national four kinds of sea water standards. With the development of aquaculture scallops in total inorganic nutrient pollutant content increased year by year.Sediment of sulfide content distribution culture zones is higher than the culture zones, monitoring all stance which conform to the kind of sediment standards. Organic carbon content distribution features:low density culture zones higher than culture zones is higher than to high-density culture zones, the culture zones of low density culture zones is high density culture zones 57 times, is more than five times the culture zones. In high-density aquaculture environment, the shellfish effect of biological deposition has no significant impact on organic carbon content.(4)Shallow sea scallops breeding influences to marine biodiversity is that it has no obvious influence on the total number of phytoplankton species, but mainly the biomass. Biomass performance more influence for high-density culture zones less than the low density culture zones is less than the culture zones. Along with the development of the Marine aquaculture year by year sea creatures total species number, individual number density, biomass, biological density are reduced.(5)Influence on WenChangYu national secondary protect animals makes the appropriate growth habitat of WenChangYu reduction and fragmentation for the change in water power by offshore aquaculture facilities led to the change of Sediment components. WenChangYu population have begun degradation because of habitat change, inhabit density, biomass and distribution range reduced year by year, age structure abnormalities.(6)ChangLi county seawater mariculture pollutants of themselves for 53416.78 t in 2009 among them N 82749.4t, P 1475.72t. The majority pollution is shellfish aquaculture pollution donsidered the amount of pollutants generated, accounting for 99% of emissions.(7)Through the analysis of the scallops breeding system N, P nutrient cycle, we estimate the raft culture of scallop N, P pollution load that is regarded the sum of breeding scallops discharge and breeding sea area sediments of nutrient mineralization regeneration, and analyzes different form proportion of nitrogen content and nutrient source quantity in different ways. We found that the culture zones sediments mineralization decomposition renewable inorganic nutrient is an important way for scallops breeding inorganic nutrient input.(8)Estimating sea scallops breeding maximum economic benefits for the optimum area is 28750 Square kilometers in ChangLi.(9)The main route of reducing sea breeding to sea area ecological environmental impact. One is the shallow sea breeding that we should reduce the breeding density and breeding scale, implement comprehensive ecological raise shellfish and seaweed, shellfish cucumber mixed breeding biological repair. The other one is pond farming in which we should better implement multiple three-dimensional ecological farming mode, use bioremediation technology, develop the factory breeding techniques, strengthen the fishery government management and science guide. |
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