During the migration and hatching process of semi-buoyant fish eggs in the high-velocity flows(2～4 m/s)oi the upper Changjiang River,collisions with navigating vessels,rocks in the river,and sediments on the riverbed are inevitable,which may damage the eggs,affecting their normal hatching,or even causing death.In this paper,free-fall experiments were conducted to study the effects of collision speeds,collision surfaces(water,sand,stone),and developmental stages on the hatching of both natural and artificial breeding fish eggs.We obtained the velocity thresholds at which fish eggs can withstand collision shock under various environmental conditions and noted the significant differences when using artificial breeding fish eggs in place of natural eggs for experimental research.Our findings also revealed that fish eggs were most sensitive to collision shock at the cell-division stage and become more resistant to such impacts as they develop further.At the last hatching stage of fish eggs,the collision veloc-ity threshold value was approximately 4.4 m/s under three varieties of collided substrates.Within this range,the hatching percent-age of fish eggs can be more than 50％.This research provides new insights into the protection of drifting fish eggs in high-speed flows,offering important references for the implementation of related river management strategies.
关键词
鱼卵孵化/碰撞冲击/速度阈值/生态保护/山区航道/长江上游
Key words
mountainous waterway/collision impact/hatching of fish eggs/developmental stages/velocity threshold/ecologi-cal protection
维普
万方数据