Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Recruitment has been linked to decreases in the ratio of age-specific mortality (M′) to mass-specific growth (G′), and year-class strength may be predicted by the age when M′/G′ = 1. Hydrological stress adversely affects these parameters for species inhabiting floodplains; however, the relationship between M′ and G′ in hydrologically variable environments is poorly understood. We evaluated age-specific mortality for six species from a 20-year time series and growth curves from otolith length-at-age data. We assessed the effect of hydrology on the transitional age (age M′/G′ = 1) at 21 sites representing a hydrological gradient. Disturbance intensity influenced age-specific mortality but had no effect on mass-specific growth. The transitional age was inversely correlated with annual density, but weakly associated with population biomass. Hydrological disturbance shifted the transitional age to older ages, reducing recruitment overall. We demonstrated that the M′/G′ transition was affected adversely by hydrological stress and can be applied to a diverse group of taxa. Growth, survivorship, and the transitional age should be evaluated to improve population modelling efforts used to predict the influence of future restoration actions.

中文翻译：

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将人口转变与波动环境中的人口动态联系起来

加拿大渔业和水产科学杂志，提前印刷。
招募与特定年龄死亡率 (M') 与特定质量增长 (G') 的比率降低有关，当 M'/G' = 1 时，可以通过年龄预测年级强度。 水文压力对栖息在洪泛区的物种的这些参数产生不利影响；然而，人们对水文变化环境中 M' 和 G' 之间的关系知之甚少。我们评估了 20 年时间序列中 6 个物种的年龄别死亡率和耳石长度-年龄数据的生长曲线。我们在代表水文梯度的 21 个地点评估了水文对过渡年龄（年龄 M'/G' = 1）的影响。干扰强度影响特定年龄的死亡率，但对特定群体的生长没有影响。过渡年龄与年密度呈负相关，但与种群生物量呈弱相关。水文干扰将过渡年龄转移到较大年龄，总体上减少了招募。我们证明了 M'/G' 转换受到水文压力的不利影响，可以应用于不同的分类群。应评估生长、存活和过渡年龄，以改进用于预测未来恢复行动影响的人口建模工作。