Better understanding of the degree of “passability” needed to sustain robust sub‐populations upstream of barriers could help address and perhaps eliminate perceived trade‐offs between fish passage and other resource management goals. We used spatially explicit, individual‐based modeling to explore the population‐level consequences of various levels of upstream passability by (1) adult resident trout, and (2) juvenile salmon. In simulations of a stream network with widespread barriers, adult trout allowed to move upstream during only the highest 4% of streamflows sustained the distribution and abundance of the population to the same extent as in a no‐barrier scenario. In simulations of salmon production in a reach fully accessible to spawning adults, the number of barriers to upstream movement by juvenile salmon did not affect the production of large outmigrants. Passage objectives less ambitious than “all the fish, all the time” may sometimes suffice to maintain populations of resident trout and anadromous salmon.

中文翻译：

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所有鱼类，无时无刻：鱼类通过项目的良好总体目标？

更好地理解维持障碍上游的强大子种群所需的“可通过性”程度，可以帮助解决甚至消除在鱼的通过与其他资源管理目标之间的权衡取舍。我们使用了基于空间的，基于个体的建模方法，以研究（1）成年鳟鱼和（2）幼鲑对上游可及性水平的不同程度的种群影响。在具有广泛障碍的河流网络的模拟中，成年鳟鱼仅在最高4％的水流期间允许向上游移动，从而在无障碍情况下维持了人口的分布和丰富程度。在产卵成虫完全可以触及的范围内模拟鲑鱼的生产，幼鲑向上游流动的障碍数量并未影响大批移民的生产。通行目标有时不如“时常放鱼”，因此足以维持鳟鱼和鲑鱼种群的数量。