竿釣釣鉤對粗首和台灣馬口魚體長的選擇性

Length Selectivity of Hook Sizes on StreamFishes Zacco pachycephalus and Candidia barbata

為臺灣河川休閒漁業之管理與其資源保育，本研究探討常用之秋田狐1號至5號釣鉤（寬2.06- 3.63 mm）對粗首　（Zacco pachycephalus）和台灣馬口魚（Candidia barbata）體長之選擇性。結果顯示這五種大小不同釣鉤對兩魚種種內族群無顯著體長選擇性，但兩魚種間則有顯著之選擇性。同一號釣鉤捕獲之粗首　體長比台灣馬口魚大，此乃因台灣馬口魚有較大之口幅所致。所捕獲台灣馬口魚有80.9%為幼魚，18.7%為亞成魚，而成魚只有0.4%。為保護河川休閒漁業資源及維持族群最大捕獲量，秋田狐釣鉤1號至5號有過小之慮。本研究建議今後在臺灣河川休閒漁業管理上，應加強各種不同漁法對現有資源影響的相關研究，提供更明確之管理依據。 For the management need of the inland angling fishery in Taiwn, length selectivity of five different sizes of Akida Nos. 1-55 hooks(width 2.06-3.63 mm) was examined for Zacco pachycephalus and Candidia barbata. The results indicated that there was no sighificant difference in the length selectivith among the hook sizes within each species, but the significance was found between the two species. For each size of the hooks, lengths of Z. pachycephalus caught were averaged sighificantly longer than those of C. barbata. This was primarily due to comparatively smaller mouth for the former species than for the latter species. For C. barbata 80.9% of fish caught was juveniles, 18.7% subadults and 0.4% asults. Apparently, the Akida Nos. 1-5 hooks are too small to maintain the maximum sustainable yield of stream fishes for angling fishery in Taiwan.