Feeding habits and growth performance of larvae and juvenile of Paralichthys olivaceus under artificial rearing conditions

The feeding habits and growth performance of Paralichthys olivaceus larvae and juvenile during the first 36 d after hatch under artificial hatchery conditions were studied.Under the temperature of 19 to 22 ℃,the prelarval stage lasted for 15 days after hatch,and postlarval stage lasted from 16th day to 35th day.From 36th day,it became juvenile fish.The relationship between total length and fish age in days was expressed as Y=1.028 2+0.701 1x-0.018 4x2+0.000 6x3,R2=0.992;The relationship between anus length and fish age in days was expressed as Y=0.179 7+0.371 7x-0.012 1x2+0.000 2x3,R2=0.960;The relationship between high length and fish age in days was expressed as: Y=0.615 6-0.069 6x+0.022 4x2+0.000 3x3,R2=0.988.As far as Paralichthys olivacens from Zhoushan area was concerned,its larval mouth opened at 3th day.The larvae and juvenile were fed with rotifers,Artemia nauplli and mixed feeds according to a designed experiment.In prelarval stage,its feeding rate ranged from 25% to 100%,fullness rate from 25% to 80%;In postlarval and juvenile stages,its feeding rate reached 100%,fullness rate 80%.Paralichthys olivacens has a highest feeding peak by day.Besides,the larvae had two highest feeding peaks,while juveniles fed only in the morning.With the development and growth of Paralichthys olivacens juveniles from Zhoushan area,its fullness period decreased and digestion period increased.Comparing to Paralichthys olivacens from north China,the development rate of Zhoushan juvenile was higher,but there was no difference in feeding habits.