滦河口文昌鱼生活史与食性初步调查

An investigation of life history and feeding habits of Branchiostoma belcheri tsingtauense outside of Luanhe Estuary

于2007和2008年的5月、8月对滦河口海域开展了文昌鱼（Branchiostoma belcheri tsingtauense）种群的生活史与食性研究。结果表明：（1）滦河口文昌鱼Ⅰ龄个体平均体长为10-14mm,Ⅱ龄为20-28mm,Ⅲ龄为36-38mm,Ⅳ龄可达44-46mm,且滦河口文昌鱼的最长体长为47.5mm。（2）滦河口文昌鱼Ⅰ龄与Ⅱ龄个体的年平均生长长度、平均生长速度相同,Ⅲ龄略高,Ⅳ龄最低。当年繁殖的文昌鱼幼体在孵化后的2-3个月内生长速度最快,接近2-2.5mm/月。（3）文昌鱼体长与体重呈指数增长关系,随着体长的增加,体重增长明显,属匀速生长型。（4）滦河口文昌鱼主要以粒径约为1mm以下的营浮游生活的硅藻为食,圆筛藻和角毛藻可能是文昌鱼的主要饵料。

The life history of Branchiostoma belcheri tsingtauens, was studied on May and August from 2007 to 2008. The results are as follows. （1）Its population consisted of four age groups of animals with lengths of 10-14,20-28,36-38 and 44-46 mm,the longest record is 47.5 mm. （2）The average growth rate and length of 1-2 years old are same,and 3-year-old group is fasted and 4-year-old group is lowest. After hatching with 2-3 months,growth rate is near to 2-2.5 mm/月. （3） Body length and weight was a significantly logarithmic relationship, belong to Uniform growth type. （4） Amphioxus was feed on diatoms which particle size is below 1 mm the,Coscinodiscus and Chaetoceros is the main food organism.