Influence of salinity on the ingestion rate of exotic species Mytilopsis sallei

外来物种沙筛贝(MyTIlOPSIS SAllEI)是一种滤食性软体动物双壳类,它有着很快的生长速度和很强的摄食能力.为了探索沙筛贝在不同盐度下对微藻的摄食能力,采用颗粒计数仪,测定了沙筛贝在15、20、25、30、35等5个盐度梯度下对等鞭金藻(ISOCHrySIS gAlbAnA)和小球藻(CHlOrEllA VulgArIS)的摄食率,比较了不同沙筛贝个体大小对小球藻的摄食率.结果表明,沙筛贝对等边金藻和小球藻的摄食率均在盐度25时达到最大,分别为3.42x104CEllS/(Ind.H)和6.72x104CEllS/(Ind.H).沙筛贝对等边金藻的摄食率随时间推移而降低,一是因为沙筛贝摄食率随着藻类密度的降低而减小,二是当海水盐度下降,沙筛贝渗透压改变,导致了进入其外套腔的海水体积的减少,从而摄食率也减少.个体较大(壳长2.8~3.5 CM)的沙筛贝对小球藻的摄食率明显高于个体较小(壳长1.7~2.4 CM)的沙筛贝的摄食率,这与其他贝类的研究结果是一致的.The exotic species Mytilopsis sallei is a filter-feeding bivalve mollusk.It has a fast growth rate and high ingestion ability.In order to explore the ingestion ability of Mytilopsis sallei to microalgae at different salinity,Particle Counter was used to determine the level of microalgae and the ingestion rates of Mytilopsis sallei on Isochrysis galbana and Chlorella vulgaris at salinity of 15,20,25,30,35 and at different sizes of Mytilopsis sallei.The results showed that the ingestion rates of Mytilopsis sallei on 2 microalgae were high at salinity of 25[the mean ingestion rates on Isochrysis galbana and Chlorella vulgaris were 3.42×104 cells/(ind·h) and 6.72 cells/(ind·h)].The ingestion rate of Mytilopsis sallei on Isochrysis galbana decreased with time.The first reason is due to the decrease of microalgae density.The second reason is that the osmotic pressure of Mytilopsis sallei was changed when salinity decreased,which resulted in less seawater entered into mantle cavity of Mytilopsis sallei.The larger individuals of Mytilopsis sallei is(shell length between 2.8 cm and 3.5 cm),the higher ingestion rate of Mytilopsis sallei on Isochrysis galbana is.The result was consistent with the ingestion rate of other shellfish.国家自然科学基金资助项目(40776066);厦门大学海洋与环境学院凌峰计划资助项