厦门筼筜湖龙须菜生长的主要影响因素

Main factors influencing the growth of Gracilaria lemaneiformis in Yundang Lagoon of Xiamen

通过在高度富营养化的海水泻湖——厦门筼筜湖开展龙须菜(Gracilaria lemaneiformis)的延绳夹苗挂养与网笼挂养实验和室内端足类啃食海藻实验,探讨了影响筼筜湖龙须菜生长的主要因素。结果显示,筼筜湖龙须菜的表观生长率为0.42%/d,实际生长率为4.80%/d,强壮藻钩虾(Ampithoe valida)的摄食量占龙须菜总生长量的91.4%。而且,筼筜湖的水流缓慢,使藻体附着最高可达2.32g/g FW的颗粒物,明显抑制了龙须菜的生长。以上研究表明,端足类的啃食作用和不良的水动力条件是导致筼筜湖龙须菜表观生长率低的主要原因。

Experiments have been done to validate the effect of amphipod grazing and hydrographic condition on the growth of Gracilaria lemaneiformis cultivated in Yundang Lagoon. The results showed that the apparent growth rate of G. lemaneiformis was 0.96 %/d, while the real growth rate was estimated to be 4.8 %/d. On one hand, Ampithoe valida, a predominant species of amphipod, may consume 91.4% of the algal growth, and thus control the biomass of G. lemaneiformis. On the other hand, slow water velocity in the lagoon caused a mass of particle adhering on the thalli up to 2. 32 g/g FW, which deteriorated the growth of the algae. As a conclusion, these are the main reasons for the low apparent growth rate of G.lemaneiformis in Yundang Lagoon.