金乌贼的早期生长发育特征

Early development of golden cuttlefish Sepia esculenta

收集金乌贼（Sepiaeseulenta）受精卵，对孵化后1-56日龄金乌贼幼体的胴背长、胴宽、体质量、骨板壳长、壳宽及骨板层数进行了测量，分析了金乌贼幼体早期发育特征和功能器官的异速生长特征。结果表明，金乌贼幼体早期发育过程中，胴背长、体质量和骨板层数分别与日龄呈指数关系，但由于器官发育的逐步完善和饵料生物种类的转变，早期发育过程可分为两个不同阶段。两个发育阶段骨板层数的增长率均显著小于1（P〈0．05），因此骨板层数不能成为判定其日龄的指标。胴体和骨板的生长均出现异速生长的特点，表明金乌贼有关运动的重要器官具有优先发育的特征。研究结果验证了在头足类早期发育过程中功能器官亦存在异速生长的假设，并为金乌贼种苗的人工培育提供了参考依据。

Early development and allometric growth patterns of Sepia esculenta larvae raised under culture conditions were analyzed. From hatching to 56-days-old, ten larvae were sampled every five days, and the dorsal mantle length, mantle breadth, body weight, cuttlebone length, cuttlebone breadth and lamella number were measured. An exponential model could describe the relationships between dorsal mantle length, body weight, lamella number and days, respec- tively. However, there were two different phases during early development, caused by the perfection of organ develop- ment and change in foods. The lamella in the cuttlebone was not deposited daily, which demonstrated the number of lamellae in the cuttlebone did not correspond to the actual age. In addition, allometric growth of the mantle and cuttle- bone were discovered, indicating that these important organs, like the swimming organ, had developed prior to others. The present results support the hypothesis that allometric growth patterns also exist in cephalopods during early ontog- eny. The data in the present study provide a basis for artificial seed breeding of golden cuttlefish.