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

本研究之主要目的在瞭解宜蘭灣海域底棲魚類的群聚特性。於2004年11月2日至12月16日間，租用大溪籍拖網漁船「新遠發63號」(總噸位52.10噸，800匹馬力)，依漁場水深分布分為A (20 ~ 50 m)、B (50 ~ 100 m)、C (100 ~ 200 m)、D (200 ~ 400 m)等4個區域，計進行33測站之漁撈試驗 (拖網之囊網網目為3 cm)。經由Shannon-Wiener index (H’) 之推估結果，A、B、C及D區之H’值分別為1.13、1.34、1.44及1.38。在各別網次方面，以第22測站之值0.41較低，經檢視其物種數僅27種，且其優勢種為真鰺 (Trachurus japonicus)，約佔該測站之80.51%。其餘各測站之H’ 值均在0.51以上，且各測站之H’ 值與水深之迴歸關係並不顯著。其次，利用Bray and Curtis之相異指數 (dissimilarity index) 及Unweighted Pair Group Mean Average (UPGMA) 之群聚分析法之分析結果，發現魚類可分為3個區域群及5個物種群，蝦類有3個區域群及4個物種群，蟹類有3個區域群及4個物種群，頭足類則可分為3個區域群及3個物種群。區域群特性隨各區域之CPUE及其主要漁獲物之物種數而異，物種群特性則隨深度及各物種之CPUE而有所不同。

The purpose of this study is to investingate the characteristics of demersal fish assemblages in Yilan Bay. A total of 33 bottom trawl operations were conducted along the waters with various depths of A (20 ~ 50 m), B (50 ~ 100 m), C (100 ~ 200 m) and D (200 ~ 400 m) by a fishing boat “Sin-Yun-Fa 63” during November 2 - December 16, 2004. The mesh size of trawl net at cod end was 3 cm. The data were then complied to analyze their catch per unit effort (CPUE). The H’ in the area of A, B, C and D were 1.13, 1.34, 1.44 and 1.38 by using the analysis of Shannon-Wiener index (H’) method. The lowest H’ at station 22 was 0.41, but examined species was only 27. Among them, the horse mackerel (Trachurus japonicus) occupied 80.51% of the catch and was the dominant species in this station. The H’ at other stations were greater than 0.51. The relationship between the H’ and the depth layer was not significant (p<0.05). Area groups and species groups were classified by using the Bray-Curtis dissimilarity index and UPGMA method. The result showed that fishes could be classed into three areas and five species groups. Crabs could be classed into three areas and four species groups. Cephalopods could be classed into three areas and three species groups. The area groups varied in CPUE and number of species. The species groups varied in depth and CPUE.