The Growth Chracteristcs Of Mytilus Edulis Linnaeu In Gouqi Island And Its Effect On The Water Quality

Indicators of water quality including temperature, salinity, pH, dissolved oxygen,turbidity, NO2-N, NO3-N, NH4-N, TN, PO4-P, TP, TOC and chlorophyll a weremeasured in blank area, monoculture area and polyculture area in Gouqi Island ofShengsi Archipelago from December2012to June2013, and the related biologicalindex of the Mytilus edulis Linnaeu in Gouqi Island from two cultured populations,namely monoculture and polyculture with kelp, including total fresh weight, freshweight of shell, fresh weight of tissue, dry weight of shell, dry weight of tissue, shelllength, shell width and shell height, were also measured. And on this base, the effectson water environment caused by culture of Mytilus edulis Linnaeu in two modelswere discussed. Analysis of variance with SPSS (two-tailed test) was used to identifyand quantify growing differences in Mytilus edulis Linnaeu of various regions. Thepossible cause of the variance was also given in the paper. Meanwhile, the effect ofphenotypic and morphometric traits on body weight of Mytilus edulis Linnaeu ofvarious regions in stage of eight month (growth turning period) were studied usingcorrelation analysis, path analysis, and regression analysis.The comparison of growing characteristics of Mytilus edulis Linnaeu in the twovarious area indicated that：(1) From December2012to April2013, the growing ofeach part in Mytilus edulisLinnaeu in two various areas were slow and sometimeseven at a state of stagnation that even caused consumption of the pre-existing energy.(2) Part of growth index showed significant differences between Mytilus edulisLinnaeu in this two culture models. The differences were mainly revealed in weightindex while the length index had a less differences. Otherwise, the growth of Mytilusedulis Linnaeu in polyculture model surpassed that in monoculture model.(3)Temperature and chlorophyll a were the key factors that influenced the growth ofMytilus edulis Linnaeu. They have some relevance with the growth of Mytilus edulisLinnaeu.The study of the effect of phenotypic and morphometric traits on body weight ofMytilus edulis Linnaeu of various regions in the stage of growth turning indicated that： The key phenotypic and morphometric traits that influenced the body weight ofMytilus edulis Linnaeu were different between various models. The phenotypic andmorphometric traits that were critical to the body weight of Mytilus edulis Linnaeu inmonoculture model were SW and BC. The degree of the determination was SW＞BC.That in polyculutre area were SW and OC with an order OC＞SW.The study of the effects on water environment caused by culture of Mytilusedulis Linnaeu in two models indicated that：(1) the temperature, salinity and pH invarious areas showed no significant difference (P＞0.05). The culture of kelpcontributed the increase of the dissolved oxygen in waters.(2) the culture of Mytilusedulis Linnaeu played a role of reducing the overall nitrogen and phosphorus nutritionin waters. However, it also increased the NH4-N concentration as well as TOC.(3) thepolyculture of Mytilus edulis Linnaeu with kelp brought down the concentration ofTN、 NH4-N and TOC in waters, which strengthened the carbon fixation andeliminated the negative effects caused by the increase of NH4-N brought by intensiveaquaculture of Mytilus edulis Linnaeu. It showed huge potential in reduding theorganic matter.(4) During the whole surveying, the principal ascending order of theconcentration of chlorophyll a was natural region, monoculture region and polycultureregion. The order of turbidity was on the contrary.