Data from: Timing is everything: fishing‐season placement may represent the most important angling‐induced evolutionary pressure on Atlantic salmon populations

Fisheries‐induced evolution can change the trajectory of wild fish populations by selectively targeting certain phenotypes. For important fish species like Atlantic salmon, this could have large implications for their conservation and management. Most salmon rivers are managed by specifying an angling season of predetermined length based on population demography, which is typically established from catch statistics. Given the circularity of using catch statistics to estimate demographic parameters, it may be difficult to quantify the selective nature of angling and its evolutionary impact. In the River Etne in Norway, a recently installed trap permits daily sampling of fish entering the river, some of which are subsequently captured by anglers upstream. Here, we used 31 microsatellites to establish an individual DNA profile for salmon entering the trap, and for many of those subsequently captured by anglers. These data permitted us to investigate time of rod capture relative to river entry, potential body size‐selective harvest, and environmental variables associated with river entry. Larger, older fish entered the river earlier than smaller, younger fish of both sexes, and larger, older females were more abundant than males and vice versa. There was good agreement between the sizes of fish harvested by angling, and the size distribution of the population sampled on the trap. These results demonstrate that at least in this river, and with the current timing of the season, the angling catch reflects the population's demographics and there is no evidence of size‐selective harvest. We also demonstrated that the probability of being caught by angling declines quickly after river entry. Collectively, these data indicate that that the timing of the fishing season, in relation to the upstream migration patterns of the different demographics of the population, likely represents the most significant directional evolutionary force imposed by angling.渔业诱导进化（Fisheries-induced evolution）可通过选择性作用于特定表型，改变野生鱼类种群的动态轨迹。对于大西洋鲑鱼（Atlantic salmon）这类重要经济鱼类而言，该过程可能对其保护与管理产生重大影响。当前多数鲑鱼河流的管理模式，是依据种群统计参数划定固定时长的垂钓季，而这类参数通常基于渔获统计数据确立。由于利用渔获统计数据估算种群统计参数存在循环论证的局限，量化垂钓的选择作用及其进化影响往往颇具难度。在挪威埃特内河（River Etne），近期布设的集鱼诱捕装置可每日对洄游进入该河的鲑鱼开展采样，其中部分个体后续会被上游的垂钓者捕获。本研究利用31个微卫星标记（microsatellites），为进入诱捕装置的鲑鱼以及后续被垂钓者捕获的多数个体构建了个体DNA分型。基于这些数据，我们得以探究垂钓捕获时间与鲑鱼入河时间的关联、潜在的体型选择性捕捞特征，以及与鲑鱼入河相关的环境变量。研究结果显示，无论雌雄，体型更大、年龄更高的鲑鱼均早于体型更小、年龄更低的个体进入河流，且体型更大、年龄更高的雌性个体种群丰度高于雄性个体，反之则不然。垂钓捕获的鱼类体型与诱捕装置采样所得种群的体型分布之间具有良好的一致性，这表明至少在该河流以及当前的垂钓季安排下，垂钓渔获能够反映种群的动态结构，未发现存在体型选择性捕捞的证据。此外，我们还证实鲑鱼入河后被垂钓捕获的概率会迅速降低。综合来看，这些数据表明，相较于种群不同结构类群的上游洄游模式，垂钓季的时间安排可能是垂钓行为所施加的最显著的方向性进化选择压力来源。