匙吻鲟仔鱼期饵料的研究

Study on the diet for paddlefish (Polyodon spathula) larvae

鱼类早期生长的细微差别对其存活以及整个生活史阶段的生长，有着不可估量的影响，而摄食是影响仔鱼期生长的最重要的外界影响因子之一。在水温19．5～20．5℃下，对匙吻鲟（Polyodon spathula）仔鱼的开口时间、适宜开口饵料和投饵率进行了研究。结果表明，匙吻鲟仔鱼在6日龄初次摄食，摄食率在7—8日龄迅速升高，9—10日龄达到100％，11-13日龄略有降低，14-15日龄迅速降低，不可逆点（PNR期）出现在15日龄；以轮虫作为开口饵料，仔鱼的存活率和生长优于丰年虫和颗粒饲料组；养殖水体中轮虫密度在120—150个／mL可满足仔鱼的生长需求。

Tiny difference of fish early life has a great effect on survival and growth in whole life history, and though the growth in larvae stage is effected by many factors, one of the most important surrounding factors is feeding. Because there were few articles on the feeding for paddlefish （Polyodon spathula） early stage,the ini- tial feeding and optimum diet as well as diet density for paddlefish were studied at water temperature 19.5 ～20.5 ℃. The result showed that the larvae initial feeding began at 6 day after the larvae were hatched out, the feeding rate increased fast at 7 day and 8 day after the hatch,and the feeding rate was 100% at 9 day and 10 day, then the feeding rate decreased in the followed 5 days, the point of no return （PNR） occurred at 9 days after initial feeding. The survival rate and growth of rotifer group were higher than other two groups. The rotifer density 120 - 150 individual/mL in water was optimum on growth of paddlefish larvae.