Sex ratios in relation to age and body size in “Honmoroko”, Gnathopogon caerulescens
Sex ratios in relation to age and body size in “Honmoroko”, Gnathopogon caerulescens
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Gnathopogon caerulescens“Honmoroko”的性别比例与年龄和体型的关系
DOI：
10.1007/s10228-014-0452-5
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发表时间：
2015
影响因子：
1.2
通讯作者：
J. Saegusa
中科院分区：
文献类型：
--
作者：
Y. Fujioka;J. Saegusa
研究了琵琶湖“Honmoroko”大量样本的年龄组成、年龄和大小的性别比。鱼的年龄为0~2岁，但多为0龄(97.9%)。雌鱼比例0龄为48.6%，1龄为73.2%，2龄为90.0%。0岁的鱼明显偏向雄性，而1岁和2岁的鱼明显偏向雌性，尽管总体上显示出平衡的性别比例。在标准长度(SL)小于9 cm的0龄鱼类中，雌性比例为48.0%或更低，与这种尺寸类别中1：1的雌：雄比例有显著差异，但4-5.99级除外。在9 cm SL或更大的大小类别中，0龄鱼中雌性比例较大，超过71.3%，与所有此类类别的平衡性别比例存在显著差异。这些结果表明，G。蓝鳍金枪鱼基本上可以被认为是一年生鱼类，其产卵习性应该导致雄性的死亡率高于雌性，从而导致1岁和2岁时性别比例偏向雌性。
The age composition, and age- and size-dependent sex ratios of mass samples of “Honmoroko”,Gnathopogon caerulescens, were examined in Lake Biwa. The fish ranged from 0 to 2 years in age, but were mostly age 0 (97.9 %). The proportion of females was 48.6 % for age 0, 73.2 % for age 1, and 90.0 % for age 2 fish. Age 0 fish were significantly male biased, while ages 1 and 2 were significantly female biased, though the grand total showed a balanced sex ratio. The proportion of females was 48.0 % or less among age 0 fish in size classes of less than 9 cm in standard length (SL) and significantly different from a female:male ratio of 1:1 in such size classes, except for the 4–5.99 class. In size classes of 9 cm SL or greater, the proportion of females among age 0 fish was greater, more than 71.3 %, with significant differences from a balanced sex ratio for all such classes. These results suggest thatG. caerulescenscan be regarded as essentially an annual fish and that its spawning habits ought to result in a higher mortality for males than females, thus leading to female-biased sex ratios at ages 1 and 2.