Abstract
This paper described the effects of suction on fry sucked by the vacuum pump system which counts the
number of seedlings fry with the sensor. The relation between suction pressure and suction velocity of the system
was presented. Finally, drainage time of fry and water on the system was counted. The results were as follows.
(1). When the lowest suction pressure was at 25kPa, so it didn't cause bad effect to the fry, the fastest suction
velocity was at l.95m/s.
(2). With the same suction pressure, the rate of fry injured was higher when fry was sucked from tail.
(3). When the ratio of fish height to the inside suction tube diameter was over ０.46 (the ratio of fish length
to the inside suction tube diameter was over 2.2), the fry would not be overtumed on the suction process.
