台灣東北部海域九孔放流與環境因數關係之研究

Abstract

九孔(Haliotis diversicolor)廣泛分佈在台灣東北部、東部各沿岸水域，是台灣重要的經濟性貝類之一。近年來由於野生九孔數量大幅減少，一些沿海縣市均會進行九孔放流以增加海域資源量。因此本研究利用碳氧穩定同位素技術，來估算臺北縣金山跳石、基隆市長潭?、宜蘭縣大?、花蓮縣石梯及台東縣長濱等5個九孔放流海域，其資源量與放流殘存率，並找出資源量與環境因數之間的關係。結果如下：(1)5 海域中九孔密度、資源量與放流殘存率分別為，臺北縣金山跳石 5.33 粒/150㎡，共有 5,664粒，殘存率為 0.73％；基隆市長潭? 5.25 粒/150㎡ , 共 2,345 粒，殘存率為0％；宜蘭縣大?1粒/150㎡，共 1,456 粒，殘存率為 0.97％；花蓮縣石梯 2.67 粒/150㎡，共 3,120 粒，殘存率為1.39％；台東縣長濱海域因無任何九孔發現，所以資源量估值為0粒，殘存率為0％。(2)海域中活九孔多分佈在離岸100公尺以淺的水域。(3)海域中九孔資源量和環境中溶氧量與藻類有正向關係，而與深度則有反向關係，其複迴歸方程式如下： Y ＝-2.0312 + 0 .5581X1+ 0.1149X2-0.2437X3 (P=0.005＜0.1) 其中Y為九孔資源量，X1為溶氧，X2為藻類，X3為深度。

Abalone (Haliotis diversicolor), which broadly distribute in the northeastern and eastern Taiwan coasts, is one of the important commercial shell species in Taiwan. Because of the declining of wild abalone stocks, some coastal counties had released abalone seeds to enhance the stock. The purpose of this study is to estimate the abundance and survival rate of abalones using oxygen and carbon stable isotope analysis in five released areas, i.e., Jin-Shan area in Taipei County, Janng-Tarn-Lii area in Keelung City, Day-Lii area in Ilab County, Shyr-Ti area in Hwalien County, and Jaang-Bin area in Taitung County, and further to find the relationship between the abundance and their environmental factors. The results are as follows: (1) The density, abundance and survival rate of released abalones are 5.33 ind. per 150㎡, 5,664, and 0.73％ in Jin-Shan area, 5.25 ind. per 150㎡, 2,345, and 0％ in Janng-Tarn-Lii area,1.00 ind. per 150㎡, 1,456, and 0.97％ in Day-Lii area, as well as 2.67 ind. per 150㎡, 3,120, and 1.39％ in Shyr-Ti area, respectively. In addition, no abalones were observed in Jaang-Bin area (2) All the live abalones were caught in 100m depth shallow area. (3) The relationships between the abalone abundance and the amount of dissolved oxygen and algae are positive, but the depth of area are negative. The equation is as follows. Y= -2.0312+0.5581X1+0.1149X2-0.2437X3 (P=0.005＜0.1) Where Y is the abundance of abalones, X1 is the amount of dissolved oxygen, X2 is the amount of algae, and X3 is the depth of area.