Population density of migratory and resident brown trout (Salmo trutta) in relation to altitude:: evidence for a migration cost
Population density of migratory and resident brown trout (Salmo trutta) in relation to altitude:: evidence for a migration cost
复制标题
DOI：
10.1046/j.1365-2656.2001.00466.x
复制
发表时间：
2001-01-01
影响因子：
4.8
通讯作者：
Degerman, E
中科院分区：
文献类型：
--
作者：
Bohlin, T;Pettersson, J;Degerman, E
1. 对于溯河鲑而言，以往研究发现的成鱼体型/年龄与溪流特征之间的正相关表明，洄游成本随着溪流长度、水量和产卵地点海拔的增加而增加。在本研究中，我们假设产卵地点的海拔高度与迁徙努力呈正相关。生活史理论预测(i)平衡卵密度，这是一种适合度测量，因此在迁徙中比在溪流中居住的种群会更快地随海拔下降，因此（ii）居住将在足够高的海拔上选择。3、由于幼鱼密度是卵密度的函数，我们假设：(a)海拔高度对迁徙种群幼鱼密度的影响强于常住种群，(b)迁徙种群幼鱼密度大于常住种群。我们使用多变量方法对瑞典164个海栖褐鳟种群和167个河栖褐鳟种群的电钓数据进行了检验(a)和(b)。这两种预测都得到了支持；与常住种群相比，迁徙种群幼鱼密度随海拔的变化更大，且下降速度更快。研究结果进一步证明，洄游成本降低了溯河鲑鱼的适应性。
1. For anadromous salmonids, the positive relations found in previous studies between adult size/age and stream characteristics suggest that the migration cost increases with stream length, water discharge and the altitude of the spawning site. In this study we hypothesized that the altitude of the spawning site is positively related to the migration effort.2. Life-history theory predicts (i) that the equlibrium egg density, which is a fitness measure, thereby will decline more rapidly with altitude in migratory than in stream-resident populations, and therefore (ii) that residency will be selected for at large enough altitudes.3, As the density of juveniles is a function of egg density, we hypothesized that (a) altitude has stronger effect on juvenile density in migratory than in resident populations, and (b) juvenile density is larger in migratory than in resident populations.4, We tested (a) and (b) using multivariate methods for electrofishing data from 164 sea-migratory and 167 stream-resident populations of brown trout Salmo trutta L. in Sweden. Both predictions were supported; the juvenile density was larger and declined more rapidly with altitude in migratory than in resident populations.5. The results are further evidence that migration costs reduce fitness in anadromous salmonids.