饵料种类、盐度、pH和规格对曼氏皮海鞘摄食率的影响

The effects of food sources,salinity,pH and body size on ingestion rates of Molgula manhattensis

以曼氏皮海鞘Molgula manhattensis为试验对象,采用静水方法在不同饵料种类(湛江等鞭金藻、扁藻、小新月菱形藻、小球藻、螺旋藻粉、稚参饵料)、盐度梯度(20、25、30、32、35、40)、pH梯度(4、5、6、7、8、9、10)和规格[大、中、小3种规格,平均湿重分别为(0.2276±0.0023)、(0.9302±0.0093)、(1.8857±0.1004)g]的条件下对其摄食率进行了研究。结果表明:(1)6种饵料对曼氏皮海鞘摄食率的影响极显著(P<0.01),摄食率大小依次为螺旋藻粉>稚参配合饵料>扁藻>湛江等边金藻>小球藻>小新月菱形藻;(2)盐度对曼氏皮海鞘摄食率的影响显著(P<0.05),在盐度为30、32时,曼氏皮海鞘对6种饵料的摄食率均较高,在盐度为20和40时,其摄食率均较低;(3)pH对曼氏皮海鞘的摄食率的影响显著(P<0.05),在pH为6、7、8和8.36(天然海水)时,曼氏皮海鞘对6种饵料的摄食率均较高,在pH为4、9、和10时,其摄食率均较低;(4)规格对曼氏皮海鞘摄食率的影响显著(P<0.05),曼氏皮海鞘对6种饵料的摄食率随其规格的增大而增大。

Effects of food sources(Isochrysis zhanjiangensis,Platymonus spp.,Nitzschia closterium minutissima,Chlorella vulgaris,spirulina powder,and formulated diets),salinity(20,25,30,32,35,and 40),pH values(4,5,6,7,8,9,and 10) and body size(small,S;middle,M;and large,L) on ingestion rates in Molgula manhattensis with diameter of 10-20mm by coughlan method.The results showed that there was significant effects of the food sources on the ingestion rates in the animals,arranging in a descendant order as: spirulina powder>formulated diets >Platymonus spp.>Isochrysis zhanjiangensis>Chlorella vulgaris > Nitzschia closterium minutissima.The maximal ingestion rate was observed at a salinity of 30 and 32 while the minimal at a salinity of 20 and 40.The maximal ingestion rates occurred at pH values of 6,7and 8,but the minimal ingestion rates was observed at pH 4 and 9.The ingestion rate was found to increase with the growth in body size(S: 0.2276 g±0.0023 g,M: 0.9302 g±0.0093 g,L:1.8857 g±0.1004 g).