Waterways and environment unit, Bundesanstalt für Wasserbau, Karlsruhe, Germany.
Animal ecology unit, Bundesanstalt für Gewässerkunde, Koblenz, Germany.
PLoS One. 2022 Feb 18;17(2):e0263964. doi: 10.1371/journal.pone.0263964. eCollection 2022.
Improving the effectiveness of fishways requires a better understanding of fish behavior near hydraulic structures, especially of upstream orientation. One of the most promising approaches to this problem is the use of model behavioral rules. We developed a three-dimensional individual-based model based on observed brown trout (Salmo trutta fario) movement in a laboratory flume and tested it against two hydraulically different flume setups. We used the model to examine which of five behavioral rule versions would best explain upstream trout orientation. The versions differed in the stimulus for swim angle selection. The baseline stimulus was positive rheotaxis with a random component. It was supplemented by attraction towards either lower velocity magnitude, constant turbulence kinetic energy, increased flow acceleration, or shorter wall distance. We found that the baseline stimulus version already explained large parts of the observed behavior. Mixed results for velocity magnitude, turbulence kinetic energy, and flow acceleration indicated that the brown trout did not orient primarily by means of these flow features. The wall distance version produced significantly improved results, suggesting that wall distance was the dominant orientation stimulus for brown trout in our hydraulic conditions. The absolute root mean square error (RMSE) was small for the best parameter set (RMSE = 9 for setup 1, RMSE = 6 for setup 2). Our best explanation for these results is dominance of the visual sense favored by absence of challenging hydraulic stimuli. We conclude that under similar conditions (moderate flow and visible walls), wall distance could be a relevant stimulus in confined space, particularly for fishway studies and design in IBMs, laboratory, and the field.
提高鱼道的有效性需要更好地了解鱼类在水力结构附近的行为，特别是在上游方向的行为。解决这个问题最有前途的方法之一是使用基于模型的行为规则。我们根据在实验室水槽中观察到的棕色鳟鱼（Salmo trutta fario）的运动，开发了一个基于个体的三维模型，并将其应用于两种水力条件不同的水槽装置进行测试。我们使用该模型来检验哪一种行为规则版本能够更好地解释上游方向的鳟鱼行为。这些版本在选择游动角度的刺激因素方面存在差异。基线刺激因素是具有随机成分的正趋流性。它还可以补充对低流速幅值、恒定的湍流动能、增加的流速加速度或较短的壁距的吸引力。我们发现，基线刺激因素版本已经解释了观察到的大部分行为。对于流速幅值、湍流动能和流速加速度的混合结果表明，鳟鱼主要不是通过这些流动特征来定向的。壁距版本产生了显著改善的结果，这表明在我们的水力条件下，壁距是鳟鱼的主要定向刺激因素。对于最佳参数集，绝对均方根误差（RMSE）很小（设置 1 的 RMSE=9，设置 2 的 RMSE=6）。对于这些结果，我们最好的解释是缺乏具有挑战性的水力刺激时，视觉感知的主导地位。我们得出的结论是，在类似的条件下（中等流速和可见的墙壁），壁距可能是封闭空间中的一个相关刺激因素，特别是对于鱼道研究和在 IBM 中、实验室和现场进行的设计。
