Application of Dual-Beam Acoustic Surey Techniques to Assess the Size Distribution of Squid,Loligo Edulis

Abstract

本研究係自1987年10月21日至1990年8月16日止，針對本省週邊水域大陸斜坡漁場進行各項影響籠具漁獲性能之因子，如籠具結構、底質、籠具置放間距及其入口數等，共計實施40測站1,940籠次漁撈試驗。調查結果摘述如下：(1)籠具投放間距為25及30公尺時，二者之單位努力漁獲量並無顯著差異，但如為10公尺時，其值却顯著降低。(2)底質為粗砂時，深海蝦之漁獲量較底質為軟泥時為多，但其他魚種則無顯著差異。(3)雙口籠具之單位努力漁獲量除深海蝦類較單口籠具為高，約為2倍外，其他漁獲種類則無顯著差異。(4)籠具結構不同，各漁獲種類之單位努力漁獲量亦有顯著差異；魚類及深海蝦類均以Ⅰ式籠具為最優，蟹類之漁獲效果普遍不佳，等足類之入籠量則以Ⅲ及Ⅴ式為最少。A study on the effectiveness of such factors as pot structures,sea bottomtype,distances between pots,and numbers of pot entrance for harvesting deepseafishes was conducted in the waters adjacent to Taiwan from 21 October1987 to 16 August 1990.The study consisted of 40 sets involving a total of1,940 traps.The results showed that(1)the CPUE[individual/(trap.hour)]of fish caught at distances between pots of 10 m,25 m,and 30 m,were 2.32,18.81,and 19.86,respectively;(2)there were no singificant differences betweencatches on sand sea bottom and mud sea bottom;in shrimps,however,theformer seemed higher than that on the latter;(3)there were no significantdifferences between catches in the double inlets and single inlet of pots;however,the catches of shrimps by the pots with double inlets were abouttwo times higher than those with single inlet;and(4)there were significantdifferences in CPUE between pots with different structures.