大鳍鳠的可量性状、长重关系和肥满度

大鳍鱯的可量性状中存在雌、雄差异,雄鱼的须和尾柄较同体长的雌鱼长,但体高不及雌鱼.长重关系和肥满度的分析表明.雌鱼的重量增长快于雄鱼;同体长的鱼,繁殖期较非繁殖期重;肥满度系数随体长的增长而降低.雌、雄鱼之间的肥满度的差异随体长的增加而增大;繁殖期鱼体的肥满度明显高于非繁殖季节;雌鱼性腺发育过程中肥满度无明显下降现象.

BIOMETRIC CHARACTERISTICS, LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTORS IN M. MACROPTERUS (pisces: Bagridae)

The biometric features, length-weight reationships and condition factors (K) of 974 specimens of the bagrid Mystusmacropterus (Bleeker) collected from the Jialing River (Southwest China) during the period from May 1986 to August 1987 and again in January 1990, are de- scribed.Differences between male and female in biometric features, such as body depth, barbie length and caudal peducle length, were found. The weight, as well as the condition factor for males are less than that for females of corresponding length. Fish collected during the repoductive period (April to July) are heavier, so their condition factors are higher, than fish collected during the nonreproductive period. The values of K decreases with increase in fish size (body length). The difference in the value of K between male and female increases with increase in body length . No obvious decrease in condition factor of female was found in accordance with the gonadal development in the repoductive period.