Rodgers Essie M, Heaslip Breeana M, Cramp Rebecca L, Riches Marcus, Gordos Matthew A, Franklin Craig E
School of Biological Sciences, The University of Queensland, Saint Lucia, Brisbane, Queensland 4072, Australia.
Department of Primary Industries, 1243 Bruxner Highway, Wollongbar, New South Wales 2477, Australia.
Conserv Physiol. 2017 May 26;5(1):cox034. doi: 10.1093/conphys/cox034. eCollection 2017.
Worldwide declines in riverine fish abundance and diversity have been linked to the fragmentation of aquatic habitats through the installation of instream structures (e.g. culverts, dams, weirs and barrages). Restoring riverine connectivity can be achieved by remediating structures impeding fish movements by, for example, replacing smooth substrates of pipe culverts with naturalistic substrates (i.e. river stones; culvert roughening). However, empirical evaluations of the efficacy of such remediation efforts are often lacking despite the high economic cost. We assessed the effectiveness of substrate roughening in improving fish swimming performance and linked this to estimates of upstream passage success. Critical swimming speeds () of two small-bodied fish, purple-spotted gudgeon (; 7.7-11.6 cm total length, BL) and crimson-spotted rainbowfish (; 4.2-8.7 cm BL) were examined. Swimming trials were conducted in a hydraulic flume fitted with either a smooth acrylic substrate (control) or a rough substrate with fixed river stones. Swimming performance was improved on the rough compared to the smooth substrate, with ( = 0.28 ± 0.0 m s, 2.89 ± 0.1 BL s, = 0.36 ± 0.02 m s, 3.66 ± 0.22 BL s, mean ± s.e) and ( = 0.46 ± 0.01 m s, 7.79 ± 0.33 BL s; = = 0.55 ± 0.03 m s, 9.83 ± 0.67 BL s, mean ± s.e.) both experiencing a 26% increase in relative . Traversable water velocity models predicted maximum water speeds allowing successful upstream passage of both species to substantially increase following roughening remediation. Together these findings suggest culvert roughening may be a solution which allows hydraulic efficiency goals to be met, without compromising fish passage.
全球范围内，河流鱼类数量和多样性的下降与通过设置河道内结构（如涵洞、水坝、堰闸和拦河坝）导致的水生生境破碎化有关。恢复河流连通性可以通过修复阻碍鱼类游动的结构来实现，例如，用自然基质（即河石；涵洞糙化）替代管道涵洞的光滑基质。然而，尽管此类修复工作成本高昂，但对其效果的实证评估往往不足。我们评估了基质糙化在改善鱼类游泳性能方面的有效性，并将其与上游通过成功率的估计联系起来。研究了两种小型鱼类——紫斑古比鱼（全长7.7 - 11.6厘米，标准体长）和红斑彩虹鱼（标准体长4.2 - 8.7厘米）的临界游泳速度。游泳试验在装有光滑亚克力基质（对照）或带有固定河石的粗糙基质的水力水槽中进行。与光滑基质相比，粗糙基质上的游泳性能有所改善，紫斑古比鱼在粗糙基质上的速度为（平均±标准误：0.28±0.0米/秒，2.89±0.1标准体长/秒；0.36±0.02米/秒，3.66±0.22标准体长/秒），红斑彩虹鱼在粗糙基质上的速度为（平均±标准误：0.46±0.01米/秒，7.79±0.33标准体长/秒；0.55±0.03米/秒，9.83±0.67标准体长/秒），两者的相对速度均提高了26%。可穿越水流速度模型预测，糙化修复后，两种鱼类成功上游通过的最大水流速度将大幅增加。这些研究结果共同表明，涵洞糙化可能是一种既能实现水力效率目标，又不影响鱼类通过的解决方案。
