Carrying Capacity Assessment & Key Ecological Process Of Cage Aquaculture In Shallow Sea

It is worthy of studying the carrying capacity of net cages aquaculture because the self-pollution has been worsening along with the scale-up of aquaculture. In this study, key biologic process, key physical process and key biogeochemical process are preliminary studied in Alilian Bay, Shandong Peninsular. Based on above studies, the carrying capacity for environment and aquaculture are estimated by modeling.Key physical process study shows that the seawater exchange period of Ailian Bay is 2.9ds.During the study of key biologic process, waste productions are studied based on field experiments and biologic-energy models. Only in the floating net cage culture zones, the cultivated fish consumed about 48t DO, excreated 3.76t ammonia and 12.37t feces (dry weight) during one production cycle. Based on the hanging nets survey and the cultivating experiment, the fouling organisms in one raft net cage can add 1~2% loading of N or P to the water. And the average population size of wild black stockfish Sebastodes fuscescens is assessed as 0.01ind.m-2 by matrix estimate method.During the study of key biogeochemical process, the fluxes of setting particulate matter inside and outside the net cages are studied by sediment traps, and the results show that the accumulation speed of waste productions from the fish culture cages reaches the maximal in August.Meanwhile, the responses of phytoplankton in Sanggou Bay to scaled up aquaculture activities and responses of environmental factors to fish aquaculture in Ailian Bay are simulated by local differential equations in the system of Matlab7.0 and one box model respectively. Based on these studies the carrying capacity for kelp, scallop and oyster in both monoculture and polyculture models in the bay are estimated by using the vanishment of phytoplankton as an index for judging the eco-healthy of intensive mariculture system. Based on numerical simulation and the second seawater quality standard, the aquaculture environmental carrying capacity of Ailian Bay is assessed as 0.08V (ind.; V is the volume of the water area, m3). While,...