叉尾斗鱼仔鱼耳石形态发育与日轮形成特征

对实验室人工繁殖的叉尾斗鱼(Macropodus opercularis)仔鱼耳石形态发育与日轮进行了观察研究.结果显示,叉尾斗鱼微耳石和矢耳石在胚胎时已出现.微耳石在仔鱼刚孵化时为圆盘状,随仔鱼发育转变为近椭圆形,孵出后19 d转变为中部圆凸两端较尖的菱形;矢耳石在仔鱼刚孵出时为圆盘状,随仔鱼发育转变为椭圆形,孵出后19 d转变为一端略尖的桃形;星耳石在仔鱼孵出后第19天才出现,呈中部略凹的椭圆形.叉尾斗鱼仔鱼耳石长径(包括微耳石和矢耳石)与鱼体全长(TL,mm)呈线性相关.仔鱼耳石上第一个轮纹在孵出后第2天形成,其后每日形成1个新轮纹,生长轮数目与仔鱼日龄(D)呈线性相关,且线性方程斜率接近于1.结论认为,叉尾斗鱼仔鱼星耳石出现时间晚,矢耳石形态在后期出现较大变化,而微耳石在胚胎时即形成,形态稳定;日轮可读性较好,故更适合做日轮研究的材料.本研究旨在为叉尾斗鱼自然种群年龄结构调查及其资源保护提供基础数据.

Otolith ontogeny and increment formation of larval Macropodus opercularis

apillus and sagitta emerge in late embryo stage. disk when the larvae began to hatch and then developed into a similar ellipse shape with the upgrowth of larvae. Nineteen days after hatching, lapillus showed a shape of rhombus with two pointed ends and a convex middle part. Sagitta was first showing a disk shape and then an elliptic one and after 19 days growth, which looked like a peach. Asteriscus did not appear until 19 days after the hatching of larvae and it was like an elliptic shape with a concave middle part. <0.001, <0.001, =356). The first ring on the otolith of larvae formed on the second day after hatching and its number increased by one every day. The figure of rings on lapillus ()] had a linear relationship with the age of larvae (d). The equations are: =1.003 4 d+0.054 5 (=165).sagittae changed largely in the late period of ontogeny. On the other hand, the lapillus of had a more stable shape and its rings had a good readability rings. So it is concluded that lapillus is more suitable for the identification of age of