Establishment of IMTA in Shanghai’s low salinity closed sea and ecological breeding of large yellow croaker

Abstract:

The Integrated Multi-Trophic Aquaculture system was established in the low-salinity closed waters of Jinshan, Shanghai for the first time, and the ecological fish culture experiment and nutrient detection analysis of large yellow croaker (Larimichthys crocea) were carried out. The results showed that after the ecological restoration by Myriophyllum spicatum and Crassostrea rivularis,the concentration of NO₃-N, NO₂-N, NH₄-N, PO₄-P and COD decreased by 58.82%, 37.50%, 55.32%, 53.85% and 45.18%, the survival rate of large yellow croaker was 94%, the specific growth rate of October was (0.22%±0.018%)/d.The condition factor, viscerosomatic index and hepatosomatic index of the ecological large yellow croaker was 1.82%±0.25%, 1.36%±0.32 %, 3.18%±0.22 %, significantly 13.7%, 25.7 %, 24.5 % lower than non-ecological large yellow croaker (P<0.05).In particular, the crude fat content of ecological large yellow croaker was 31.14%±0.11%, which was significantly lower than that of non-ecological large yellow croaker (42.46%±0.08%) (P<0.05).The water content, crude protein content and ash content of ecological culture were 66.79%±5.94 %, 3.84%±0.0029 % and 73.15% ±0.069%,which were significantly higher than non-ecological culture 54.91%±4.88 %, 3.14%±0.0046% and 65.96%±0.033 % (P<0.05).The essential amino acid valine, methionine, isoleucine, leucine, threonine, phenylalanine and lysine of ecological culture were 20.7%, 36.0%, 22.1%, 20.5%, 20.1%, 25.2%, 18.2% significantly higher than non-ecological culture (P<0.05).The above results showed that the large yellow croaker can be cultured in 5-6 low salinity waters, and the ecological cultured large yellow croaker had higher nutritional value.