Tuor Kimberly M F, Heath Daniel D, Shrimpton J Mark
Fisheries Protection Program, Fisheries and Oceans Canada Whitehorse Yukon Canada.
Great Lakes Institute for Environmental Research and Department of Integrative Biology University of Windsor Windsor ON Canada.
Ecol Evol. 2020 Oct 17;10(23):13198-13210. doi: 10.1002/ece3.6912. eCollection 2020 Dec.
Adult size, egg size, fecundity, and mass of gonads are affected by trade-offs between reproductive investment and environmental conditions shaping the evolution of life history traits among populations for widely distributed species. Coho salmon have a large geographic distribution, and different environmental conditions are experienced by populations throughout their range. We examined the effect of environmental variables on female size, egg size, fecundity, and reproductive investment of populations of Coho Salmon from across British Columbia using an information theoretic approach. Female size increased with latitude and decreased with migration distance from the ocean to spawning locations. Egg size was lowest for intermediate intragravel temperature during incubation, decreased with migration distance, but increased in rivers below lakes. Fecundity increased with latitude, warmer temperature during the spawning period, and river size, but decreased in rivers below lakes compared with rivers with tributary sources. Relative gonad size increased with latitude and decreased with migration distance. Latitude of spawning grounds, migratory distance, and temperatures experienced by a population, but also hydrologic features-river size and headwater source-are influential in shaping patterns of reproductive investment, particularly egg size. Although, relative gonad size varied with latitude and migration distance, how gonadal mass was partitioned gives insight into the trade-off between egg size and fecundity. The lack of an effect of latitude on egg size suggests that local optima for egg size related to intragravel temperature may drive the variation in fecundity observed among years.
成年个体大小、卵的大小、繁殖力和性腺质量受到生殖投资与环境条件之间权衡的影响，这些条件塑造了广泛分布物种不同种群生活史特征的进化。银大麻哈鱼具有广泛的地理分布，其分布范围内的不同种群经历着不同的环境条件。我们采用信息论方法，研究了环境变量对不列颠哥伦比亚省各地银大麻哈鱼种群中雌鱼大小、卵大小、繁殖力和生殖投资的影响。雌鱼大小随纬度增加而增大，随从海洋到产卵地的洄游距离增加而减小。孵化期间砾石层内温度处于中等水平时卵的大小最小，卵大小随洄游距离增加而减小，但在湖泊下游的河流中卵大小会增大。繁殖力随纬度、产卵期温度升高以及河流规模增大而增加，但与有支流源头的河流相比，湖泊下游河流中的繁殖力降低。相对性腺大小随纬度增加而增大，随洄游距离增加而减小。产卵地的纬度、洄游距离以及种群所经历的温度，还有水文特征——河流规模和源头水源——对生殖投资模式，尤其是卵大小的形成具有重要影响。尽管相对性腺大小随纬度和洄游距离而变化，但性腺质量的分配方式有助于深入了解卵大小与繁殖力之间的权衡。纬度对卵大小没有影响，这表明与砾石层内温度相关的卵大小局部最优值可能导致了多年间观察到的繁殖力变化。
