唐鱼仔鱼耳石的形态发育及日轮

Otolith Ontogeny and Increment Formation in Larval Tanichthys albonubes

观察了实验室人工繁殖饲养的唐鱼(Tanichthys albonubes)仔鱼耳石形态发育,研究了其生长轮的沉积规律。唐鱼仔鱼耳石长径与鱼体全长(TL)均呈线性相关,其关系式为:微耳石Dl=0.019 6TL-0.031 0(r=0.961 6,P<0.001,n=218),矢耳石Ds=0.027 6TL-0.043 7(r=0.924 0,P<0.001,n=219),星耳石Da=0.016 6TL-0.004 1(r=0.369 6,P<0.001,n=44)。仔鱼耳石上第一个轮纹在孵出后第2 d形成,生长轮数目与仔鱼日龄(D)呈线性相关,其斜率与1无显著差异,因此生长轮为日轮,其关系式为:微耳石LI=1.006D-1.700 1(r=0.994 2,P<0.001,n=205),矢耳石SI=0.953 8D-0.911 6(r=0.993 5,P<0.001,n=161)。生长过程中矢耳石形状变化较大,星耳石出现时间较晚,而微耳石形状稳定,日轮可读性较好,故更适合作为日轮研究的材料。

Tbe morphology, formation and deposition of the first increment, and the rate of increment deposition were studied for sagittae, lapilli, and asterisci from Tanichthys albonubes. Sagittae and lapilli are apparently formed before hatching, and asterisci were observed 23 - 36 days after hatching. The diameters of lapilli, sagitlae and asterisci were linearly related to fish length, the equation were D1 = 0.019 6TL- 0.031 0 （ r = 0.961 6, P 〈 0.001, n = 218）, Ds =0.0276TL-0.0437 （r=0.9240, P〈0.001, n=219）, Da=0.0166TL-0.0041（r=0.3696, P〈0.001, n = 44）. The first growth increment in otoliths was observed one day after hatching. The number of increments on lapilli （LI） and sagittae （SI） were linearly related to daily age （D） of larvae, the equation were LI = 1.006D - 1.7001 （r=0.9942, P〈0.001, n =205）, SI=0.953 8D-0.911 6 （r=0.993 5, P〈0.001, n = 161）. Because of their readability and conservative growth, lapilli are considered the preferred otolith structure for age determination of T. albonubes.