Abstract
The drifting behavior of fish eggs is crucial for early-stage fish
resources estimation, fish spawning ground identification and river
management. To understand their move patterns in longitudinal, vertical,
and lateral directions in deceleration flow, self-made model fish eggs
similar to the real ones in the upper reaches of the Yangtze River was
adopted to carry out the experiments. And the experiments were carried
out in a 28 m flume equipped with particle tracing system (PTV) with
different average decelerating flow velocity. The results showed that
the longitudinal velocity of fish eggs was 0.83 times of the flow
velocity, while the vertical velocity of fish eggs was not significantly
related to the flow velocity. During drifting, fish eggs spread almost
uniformly to both sides along the central axis of the main current. The
results are useful for early-stage fish resource conservation and
ecological scheduling of the rivers with rapid flows. However, more
studies are needed to confirm whether high flow velocity is beneficial
to the survival of drifting fish eggs.