FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

Ichthyoplankton samples were collected using bongo nets with mesh sizes of 200 μm and 330 μm at ten stations in the in the Taiwan Strait and the waters of northern Taiwan. A total of 651 fish larvae representing 50 families were identified. Members of the Clupeidae, Myctophidae, Engraulidae, Carangidae, Scombridae, Bregmacerotidae, Synodontidae, and Bothidae families accounted for 70.7 % of the total larvae collected. The plankton samples collected did not differ significantly between the two mesh sizes in terms of mean filtered volume or the amount of organic material. Similarly, the overall larval fish density, mean length, and length distribution of the dominant taxa, with the exception of the Engraulidae family, also showed no significant differences between the two mesh sizes. However, the size distributions of the dominant families indicated that the morphologies of the fish larvae did influence the efficiency of mesh retention. Relatedly, the results indicated that the extrusion of filiform or smaller fish larvae has to be taken into account to obtain more robust estimates from 330 μm mesh nets when abundances are used in quantitative population studies. Nonetheless, the present study confirmed that icthyoplakton samples collected with the two mesh sizes are comparable when used in qualitative studies of community structures in the in the Taiwan Strait and the waters of northern Taiwan.