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

箱網養殖的海鱺(Rachycentron canadum)幼魚容易受發光菌感染(Photobacterium damselae subsp. Pisicida)，導致低活存率。本計劃之目的為探討野生海鱺幼魚在池中所培育成的種魚之F1子代對發光菌的抗病力。野生幼魚所培育成的種魚在池中無法自然產卵，因此受精卵的來源為種魚經由人工催熟後，置於池中讓其自行交配產卵，由多尾的雄魚與成熟的雌魚交配所獲得。近親化海鱺苗的來源，取自目前已同源繁衍數代的海鱺子代。魚苗培育至幼魚階段，再進行抗病力試驗。以注射或浸泡發光菌液的方式，進行抗病力試驗。結果顯示海鱺幼魚所培育成的種魚之F1子代，經細菌感染後，有較慢發生死亡的現象，感染後2-3天有較高的活存率，然而細菌感染濃度如過太高，亦會造成高死亡率，適當濃度的抗病力試驗，野生海鱺種魚的F1子代比近親化的海鱺子代活存率高20%。本試驗證實以野生海鱺作為種魚，配合進行往後的育種選拔，為改善海鱺幼魚在海上箱網養殖期間，低存活率的重要策略之一。

Cage-cultured cobia juveniles are susceptible to Photobacterium damselae subsp. piscicida, resulting in low survival rates. The purpose of this study is to investigate the disease resistance to Photobacterium damselae subsp. piscicida of F1 progeny, obtained from broodstock cultivated from wild-caught cobia juveniles. Results show that the disease resistance of F1 progeny in the wild broodstock line is stronger than those of the inbred line. Mortality in the F1 progeny still occurred when infected with high concentrations of bacteria, although this occurs later than those from the inbred line after infection. This study shows that producing disease-resistant progeny from wild broodstock is an important strategy in improving the low survival rate of cobia juveniles in the cage-culture stage.