A Classification Method for Fish Swimming Behaviors under Incremental Water Velocity for Fishway Hydraulic Design

Abstract

In fishway design, the combination of fish swimming behaviors and suitable fishway hydraulic characteristics increases the fish passage efficiency. In this study, the most representative grass carp among the “four major Chinese carps” was selected. Under conditions similar to the time period for feeding migration, juvenile grass carps were targeted to study the swimming characteristic indicators (i.e., critical and burst swimming speeds) and swimming behaviors that were closely associated with fishway hydraulic design using the incremental water velocity method in a homemade test water tank. (1) The study results reveal that both the absolute critical (Ucrit) and burst (Uburst) swimming speeds increased linearly with increasing body length and both the relative critical (U’crit) and burst (U′burst) swimming speeds decreased linearly with increasing body length. There existed a quantitative relationship between Uburst and Ucrit, which could facilitate the fishway hydraulic design. (2) This study analyzed the effects of water velocity changes on fish swimming behaviors and proposed a classification method for four fish swimming behaviors—swimming freely, staying, dashing at a long distance, and dashing at a short distance—of tested fish during the process of adapting to water velocity changes interspersed with one another. The entire swimming process under the incremental water velocity was divided into four stages. (3) This study suggests that the maximum water velocity of the mainstream in a fishway using grass carp as the major passage fish should not exceed 52–60% Uburst at stage 1. For the high-water velocity areas of a fishway, such as vertical slots and orifices, the optimal water velocity should not be higher than 76–79% Uburst at stage 2 and should absolutely not exceed 90–96% Uburst at stage 3.

Rheotaxis Response Based on Sexual Dimorphism in the Green Swordtail Fish, Xiphophorus hellerii

“…Morphological adaptation of stream fish is mostly on the locomotion part, consisting of a variation on the abdominal shape, caudal regions, and fins (Shuai et al, 2018;Hanif et al, 2019). The slender body of stream fish is crucial to enhance the ability to swim against the stream (Mu et al, 2019;Wagle et al, 2015). Dunn et al (2020) reported population morphological variations of Galaxias brevipinnis, Galaxias gollumoides, and Galaxias Vulgaris in lotic habitats have a slender body to their lentic-habitats counterparts.…”

Distribution of cyprinids in the stream during their spring upstream migration

“…Researchers [17][18][19][20], when studying swimming characteristics in several species from the family of Cyprinidae, noted significant differences between individuals of different sizes and species; with increasing age and size of the fish's body, the swimming characteristics of the individual also increase, while it was established [21] that the water flow velocity and substrate are the main factors affecting the choice of biotope, while the first of them is considered the most significant. This pattern explains the distribution of a larger percentage of large fish from the family Cyprinidae at a high-velocity section of the watercourse -No.…”

Coupling 3D hydraulic simulation and fish telemetry data to characterize the behaviour of migrating smolts approaching a bypass

“…Between 6 Â 10 À4 N and fish thrust at maximum sustained speed (6 Â 10 À3 N), fish were considered to be in an "endurance state". Maximum sustained speed corresponds to the maximum speed reachable in endurance swimming: i.e., an activity that can be maintained over a long period of time and uses only aerobic muscle fibers (Mu et al 2019). Above the maximum sustained speed, the fish was in a "burst state".…”

“…Above the maximum sustained speed, the fish was in a "burst state". Burst swimming is swimming behaviour that cannot be maintained for a long time, that requires both aerobic and anaerobic muscle fibers, and can correspond to unsuitable predation conditions or breaking through water flow barriers (Mu et al 2019).…”