Environmental and Genetic Sex Determination in Fishes

这个项目的目的是展示季节性的 温度对性比的影响是适应性的。 身穿海军陆战队 鱼，大西洋银汉鱼（Menidia），热对性别的影响 这一比例导致女性在一年中生产早于 男性。 在最后，雌性往往比雄性大。 夏季生长季节，大概是因为他们经历了一个 由于出生较早，生长期较长。 大尺寸 对于女性的生殖成功似乎更重要 比雄性银汉鱼要多 科诺菲尔医生会检查 具有体积大、生长期长的优点。 他的方法 是比较生长季节长短对 雌性和雄性的身体大小之间的纬度种群 经历着不同生长季节的银鱼 持续时间。 在这些人群中， 性别比例也有差异。 他还将衡量如何 人口改变增长率，试图补偿 生长季节的长度差异， 纬度 这项研究的结果将大大增进我们的知识 环境性别决定是如何进化的 它还将 帮助我们理解特定物种的种群 补偿生长季节长短的差异。 这 信息对基础生态学研究很重要。 但 它在鱼类养殖中也是有用的， 在环境上操纵性别比例，或者选择种群 从自然界中获得的最高增长率， 优势的

The objective of this project is to show how the seasonal effects of temperature on sex ratio are adaptive. In a marine fish, the Atlantic silverside (Menidia), thermal effects on sex ratio result in females being produced earlier in the year than males. Females tend to be larger than males at the end of the summer growing season, presumably because they have experienced a longer growing season by virtue of earlier birth. Large size appears to be more important to reproductive success in female than male silversides. Dr. Conover will examine the related benefits of large size and longer growing period. His approach is to compare the effects of length of the growing season on female and male body sizes among latitudinal populations of silversides that experience very different growing season durations. In these populations the level of thermal control on sex ratio is also known to vary. He will also measure how populations alter growth rate in an attempt to compensate for the differences in length of the growing season that occur with latitude. The results of this study will greatly enhance our knowledge of how environmental sex determination evolves. It will also help us to understand how populations of a given species compensate for differences in length of the growing season. This information is important to fundamental ecological research. But it will also be useful in fish culture, where the ability to environmentally manipulate the sex ratio, or to select stocks from nature with the highest growth rate, would be highly advantageous.