野生、養殖及標誌放流台灣鏟頷魚覓食行為比較研究

Abstract

為因應漁業資源日益減少，魚類復育放流在全世界被廣為採用，但放流成效常因事前評估工作不足、施作不當使效果不佳，而缺乏中間育成培養放流物種野外生存能力亦為可能敗因之一，在生物成長、繁衍、遷移或避敵等重要行為都仰賴能量投注，覓食行為重要性無庸置疑，對群體生活的物種更加重要，對魚類而言，群聚行為已被廣泛研究，但較偏重同一群體內個體的比較，來自不同群體的個體間影響研究較少，然若不詳加釐清各群聚之間在覓食行為上之食物認知能力或種間競爭力等變數，放流施作恐不易成功，再則，放流通常會造成施作區域種間族群比例短時間內急遽失衡，在此前提下，究竟是原生群體受外來群體影響較鉅抑或完全相反，情況仍待諸多研究驗證，因此，本研究運用隔板試驗台灣鏟頷魚野生、放流再捕及養殖三族群間單一族群、兩兩族群三比三混合群聚以及五比一混合群聚中第一尾通過隔板、第一尾攝食、兩尾攝食、三尾攝食共四項時間點輔以表現行為來探討各群聚組合在覓食藻類及飼料上的差異，結果顯示，單一族群在覓食各自長期攝食的食物上皆快速，又當群聚成員越單純，整體覓食的表現越佳，而當其中有一名成員被不同群的個體取代時，群體覓食表現明顯受其影響，而當群聚內兩群個體數量數相當時，覓食表現較多樣分歧，綜合上述結果顯示台灣鏟頷魚群聚覓食行為受不同群個體顯著的影響。

The fisheries resources depleted in recent decades, fish stocking were widely adopted to enhance the resources in many countries. The release effects were usually poor due to its assessments not enough, wrong operation or low survival and foraging ability of fishes, especially for those group-living animals which often got social information to elevate individual fitness. The shoaling behavior is important for information transfer, anti-predator responses and foraging ability for individuals among shoal but a few studies between shoals. The purpose of the study is to compare the foraging behaviors among three groups, i.e., the wild, the hatchery, and the mark-released Taiwan shoveljaw carp (Varicorhinus barbatulus). Three shoals for six individuals from same group, six shoals for five-one from two groups and three shoals for three-three from two groups were selected, respectively. There were four time recorded, i.e., the time for the first individual swim through opaque partition, the first individual begin to feed algae or artificial diets, two individuals together feed, and three individuals or above together feed, besides which groups were also identified. The results are as follows. The four recorded time for the six individuals from same group were shorter for all shoals, in other words, those groups have the strongest explored behavior and have faster foraging ability for their habitual foods. The foraging patterns were influenced among the five-one from two groups and were divergent for three-three from two groups. In summary, the foraging behaviors of shoals were influenced by the individuals from different groups obviously.