匙吻鲟摄食器官数量性状胚后发育研究

匙吻鲟摄食器官发育期较长，全长６５．５ｍｍ，以前为仔稚鱼期，摄食方式为吞食，适口饵料粒径大于０．３ｍｍ，阶段口径，口宽及齿的数量发育较快。全长６５．５ｍｍ后开始出现鳃耙，其长度及过滤面积呈幂函数增长，显示具有较强的过滤能力。滤食阶段，鳃耙间距小于０．１ｍｍ，饵料规格与鳙相似。本文对匙吻鲟口及鳃耙数量发育进行了回归分析，并探讨了其摄食器官数量性状与食性变化的关系。

STUDY ON POST-EMBRY DEVELOPMENT OF QUANTITATIVE CHARACTERS OF FEEDING ORGANS IN PADDLEFISH, POLYODON SPATHULA

The period of development of feeding organs is long in paddlefish, Polyodon spathula. Fish feed live food organisms by oral and teeth until 65. 5mm total length. In this stage, oral width and diameter developed quickly, and the size of food organisms is more than 0. 3mm. Gill rakers were not well developed until 65. 5mm of total length. The increasing rate of length and filtering-size of gill rakers is exponential in relation to the total length of fish. The diameter of food organisms which could be filted between gill rakers is more than 0. 1mm which is similar to that of another filt-feeding fish, big head carp (Aristichthysnobilis). The relationship between quantitative characters of feeding organs and change of feeding behaviour was discussed in this paper. Against the total length of paddlifish, the regression analysis of those quantitative characters was also made.