Studies on artificial control of reproductive cycle in fishes.

1.研究了淡水鲤科鱼类Hnathopogon caerulescens和海水蜻蜓Repomucenus beniteguri(Repomucenus Beniteguri)的繁殖活动与水温和光照周期的关系。(1)红鱼对环境因子的反应与金鱼相似，即光周期依赖于温度，高温抑制性腺成熟。随着水温的升高，短日照对成熟度的抑制作用更明显。秋季气温下降时，随着短日照抑制作用的减弱，性腺开始复燃。虽然在春季至初夏的产卵季节，维持成熟需要较长的光周期，但在日照较长的情况下，夏季的高温抑制了性腺的活动。(2)春季随着温度的升高(18ﾟC以上)，托比努梅里鱼开始产卵，随着温度的进一步升高(28ﾟC以上)，暂时停止产卵。…随着秋季温度的下降(低于24-25ﾟC)，更多的产卵恢复，产卵持续低于14ﾟC。实验发现，与honmoroko不同，长光周期对这种鱼的性腺活动有抑制作用。从3月份开始，在16L、18L和20L的长光周期下饲养虹吸鱼亲鱼一年左右。在长日照条件下，性腺复燃提前，16L龄雌鱼在10月份达到产卵高峰，其他组在11月份达到产卵高峰。三组雄鼠的受精时间均比自然条件组提前一个月。这表明，长光周期处理可以补偿雄性成熟的延迟，这是许多选择早期产卵雌性的孵化场的问题。3以金鱼为实验对象进行了两个实验。一种是长期暴露于24ﾟC或16ﾟC联合16L或12L，另一种是一年内多次短期暴露于从自然条件转换而来的四个方案。这些实验表明，随着温度的升高，光周期变得更加清晰，但长光周期对性腺成熟的促进是短暂的。高温和长光周期对雌性的性腺有抑制作用，而对雄性没有抑制作用。对于洪鱼和金鱼血浆成熟相关激素的水平，雌鱼的雌二醇-17β和雄鱼的睾酮与性腺成熟程度相关，但促性腺激素的含量随着温度的升高而增加，无论成熟期都是如此。较少

1. The effects of water temperature and photoperiod on the reproductive activity were investigated in two fishes, freshwater cyprinid fish Honmoroko (Gnathopogon caerulescens) and seawater dragonet Tobinumeri (Repomucenus beniteguri), as new species. (1) Honmoroko showed a similar response with goldfish to environmental factors, that is, photoperiodism was dependent on temperature and high temperature suppressed gonadal maturation. Short daylength depressed maturation more effectively as water temperature increased. In autumn when temperature decreased, gonadal recrudescence started with the diminution of inhibitory effect of short daylength. Though maintenance of maturation needed long photoperiod in the spawning season of spring to early summer,high temperature in summer suppressed the gonadal activity when daylength was still long. (2) Tobinumeri began to spawn as temperature rose (above 18ﾟC) in spring, and stopped spawning temporally with further rise of temperature (above 28ﾟC). … More Spawning resumed with the fall of temperature in autumn (below 24-25ﾟC), and spawning continued below 14ﾟC. It was noticed experimentally that unlike honmoroko, long photoperiod had suppressive effect on gonadal activity in this fish.2. Rainbowtrout broodstock were reared under long photoperiods, 16L, 18L and 20L for about one year from March. Gonadal recrudescence advanced under long daylength, and at 16L females reached spawning peak in October whereas the peak of other groups were November. The spermiation of males of three groups started one month earlier than those of natural condition group. It was suggested that long photoperiod treatment can compensate the delay of male maturation which is a problem of many hatcheries where early spawning females have been selected.3 Two experiments were conducted with goldfish. One was long term exposure to 24ﾟC or 16ﾟC combined with 16L or 12L, and the other was short exposure to four regimes transferred from natural condition several times in a year. These experiments revealed that photoperiodism became clearer as temperature increased, but enhancement of gonadal maturation by long photoperiod was transient. It was also observed that high temperature and long photoperiod was suppressive to gonads in female but not in male.4. As to the plasma level of maturation related hormones in honmoroko and goldfish, estradiol-17beta of female fish and testosterone of male fish were correlated with degree of gonadal maturation but gonadotropin contents increased with the temperature regardless of maturational stage. Less