Relationship between Upstream Swimming Behaviors of Juvenile Grass Carp and Characteristic Hydraulic Conditions of a Vertical Slot Fishway

Ping Cao,Xiangpeng Mu,Wanyue Zhen,Xiang Li,Xiuying Wang,Baoligao Baiyin

doi:10.3390/w13091299

Abstract

The successful fish upstream movement through a dam/gate is closely associated with the hydraulic conditions of a fishway. To improve the passage efficiency, this study investigated the upstream swimming behaviors of juvenile grass carp, a representative fish of four major Chinese carps, under characteristic hydraulic conditions of a designed vertical slot fishway model. The impacts of different discharges and baffle lead angles on the successful movement of test fish were analyzed, and the selection of the movement trajectory was studied through overlay of their upstream swimming trajectories on the water flow field resulting from numerical modeling. We found that under the same discharge, the percentage of successful test fish movement with a lead angle of 45° was higher than 60° and 30°. Within a fixed lead angle, the higher the discharge, the lower the percentage of successful movement. During upstream movement, the test fish had a preferred water velocity of 0.01–0.45 m/s in the pool, and avoided areas where the turbulence kinetic energy (TKE) was greater than 0.012 m2/s2. These results provide a basis for the hydraulic design of vertical slot fishways and a reference for studying swimming behaviors of other fish species.

Highlights

The four major Chinese carp, including (Mylopharyngodon piceus (Cyprinidae, Richardson)), grass carp (Ctenopharyngodon idellus (Cyprinidae, Cuvier et Valenciennes)), silver carp (Hypophthalmichthys molitrix (Cyprinidae, Valenciennes)), and bighead carp (Aristichthys nobilis (Cyprinidae, Richardson)), are important economic fish species in China and belong to potamodromous fish [1]
Fishway engineering is important for ecological protection or remedial projects to allow fish pass through [6]. Their hydraulic design should be consistent with the swimming behavior of the fish species in case [7], otherwise it will be affecting the fish passage efficiency and even leading to migration failure [8]
Through overlay analysis of the water flow field of the numerical modeling and the swimming trajectories of the test fish, we studied the selection of the movement trajectory by the test fish under different characteristic flow conditions

Summary

Introduction

The four major Chinese carp, including (Mylopharyngodon piceus (Cyprinidae, Richardson)), grass carp (Ctenopharyngodon idellus (Cyprinidae, Cuvier et Valenciennes)), silver carp (Hypophthalmichthys molitrix (Cyprinidae, Valenciennes)), and bighead carp (Aristichthys nobilis (Cyprinidae, Richardson)), are important economic fish species in China and belong to potamodromous fish [1]. Fishway engineering is important for ecological protection or remedial projects to allow fish (or other aquatic species) pass through [6]. Their hydraulic design should be consistent with the swimming behavior of the fish species in case [7], otherwise it will be affecting the fish passage efficiency and even leading to migration failure [8]. Many other studies reported much lower efficiencies, including several non-effective facilities [10,11] These indicate that current fishways are far from achieving the primary conservation goal of restoring the connectivity of freshwater ecosystem

Methods

Results

Discussion

Conclusion