農業部-水產試驗所全球資訊網農業部-水產試驗所全球資訊網

為瞭解不同的網目大小的浮游生物網對仔稚魚採集結果之影響，本研究利用水試一號試驗船於臺灣海峽及北部海域共10個測站，以網目分別為200 μm及330 μm之Bongo浮游生物網進行仔稚魚採集。10個網次共採得50科651尾仔稚魚，其中大於2% 的優勢種有8科460尾 (佔70.7%)，依次為鯡科 (Clupeidae)、燈籠魚科 (Myctophidae)、鯷科 (Engraulidae)、鰺科 (Carangidae)、鯖科 (Scombridae)、海鰗鰍科 (Bregmacerotidae)、合齒魚科 (Synodontidae)、鮃科 (Bothidae)。在拖曳特性的部分，檢定結果顯示濾水體積與濕重的平均值在兩個網目間並沒有差異，仔稚魚總密度、平均體長及體長分布在各優勢種間並無網目間差異 (鯷科除外)。然而，觀察各優勢仔稚魚的體長分布顯示仔稚魚的體型差異可能會影響到不同網目的採集效率，亦即細長型仔稚魚存在因水流擠壓而穿逸330 μm網目的情形，因此，有關仔稚魚豐度量化相關研究若將逃逸率納入考量應可獲得較為精確之估值。群集分析的分群結果在兩種網目間相當的類似，顯示在臺灣海峽及北部海域以200 μm或330 μm的網目採集仔稚魚，並不會造成群聚分析時的差異。

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.