鳗鲡(Anguilla japonica Temminck  Schlegel)繁殖生物学研究——Ⅰ.下海鳗鲡雌雄性状差异和鉴别

STUDIES ON THE BREEDING BIOLOGY OF THE EEL (ANGUILLA JAPONICA TEMMINCK SCHLEGEL)——Ⅰ.EXTERNAL CHARACTERISTICS AND SEX DISTINCTION OF MALE AND FEMALE EELS AT SEAWARD MIGRATING PERIODS

摘要: 通过比较鳗鲡的眼径、眼间距、吻形等外部特征能比较可靠地鉴别雌雄两性。这些形态上的测量数据经“判别函数”的计算,确定了两性之间的差别。运用形态上的差异鉴别400—600毫米体长组的雌雄鳗,准确率可达到90%。座标图表明体长的分布自然地区分为雌雄鳗,体长在600毫米以上者全为雌鳗,体长400毫米以下者全为雄鳗。雌雄两性体长和体重关系为W=0.0000001285L3.015。体长400—600毫米的鳗鲡的体长和体重的直线回归系数(b)依性别而有所不同。雄鳗为0.887(W=0.887L-280.20);雌鳗为1.150(W=1.150L-376.73)。雄性肥满度为1.15±0.052,雌性为1.42±0.053,以上两对数值在两性间都存在显著差异。

Abstract: Methods of identifying the sex of eels at the seaward migrating period were studied.Expernal characteristics,by comparing the diameter of eyes,interorbital space,the shape of snout,etc,are sufficiently reliable for the identification of both sexes.These morphological dimensions when calculated with the aid of distinguish function,confirm the differences between the two sexes. Consideration of morphological differenees of the 400-600 mm size group, permits separation of the sexes with 90 per gent accuracy. Plotting of size distribution separates naturally one sea from the other.