菊黄东方鲀仔稚鱼的生长、发育及行为生态

Growth,development and behavior ecology of tawny puffer(Takifugu flavidus)larvae and juveniles

在大批量苗种培育条件下,通过对菊黄东方鲀胚后发育阶段的观察、测量和摄影,研究了菊黄东方鲀仔、稚鱼的生长、发育及行为生态特点。结果显示,仔稚鱼发育分为前期仔鱼、后期仔鱼、前期稚鱼、中期稚鱼和后期稚鱼5个阶段,每个阶段由若干个时期组成,总共为17个时期。在盐度10.0～13.5、温度20.5～26.0℃条件下,鱼苗历时35d完成了从初孵仔鱼至夏花鱼种的发育。期间,鱼苗食性经历了开口和转食配合饲料2个关键时期。食物转换依次为卵黄、轮虫、卤虫幼体、中型枝角类、大型桡足类和枝角类、底栖生物和虾类幼体、配合饲料。同时,鱼苗完成了由水体中上层向中下层活动区域的转变。游泳行为经历了平游、巡游和池塘觅食巡游3个模式。鱼苗在后期仔鱼阶段特定生长率最低,为3.18%/d,中期稚鱼阶段最高,达13.31%/d。全长与日龄及积温均呈指数函数增长相关(y=aebx)。肛前长和体高相对于全长均呈有拐点的、可分段的异速生长相关(y=axb)。拐点分别出现在鱼苗16～17日龄、全长10.0mm和16～17日龄、全长10.5mm。在拐点前,肛前长、体高生长优于全长(b>1)。拐点后则相反(b<1)。根据研究结果,建议当菊黄东方鲀仔鱼4日龄开口时,采用S型褶皱臂尾轮虫,并保持轮虫密度(5～7ind/mL);及时分池,时间在10～12日龄为好;下塘时间为20日龄左右;在鱼苗转食配合饲料后(35日龄),及时过筛、分级养殖等,提高菊黄东方鲀苗种培育存活率。

The observations on the post embryonic development of larvae of tawny puffer（Takifugu flavidus）at each stage have been made.The photography and measurement were carried out on their growth,development and behavior ecology.The results showed that the post embryonic development of tawny puffer could be divided into 5 stages,i.e.early larva stage,late larva stage,early juvenile stage,mid juvenile stage and late juvenile stage.Each stage consists of several periods and there are 17 periods in total.The post embryo development lasted for 35 d from newly hatched larva to young fish under water temperature 20.5-26.0 ℃ and the salinity 10.0-13.5.There were 2 key periods of fry feeding habit changing,i.e.initial feeding and ingest artificial feed,and followed by the sequence of feed,yolk,rotifer,Artemia spp.larvae,medium-sized cladoceras,large copepods and cladoceras,benthic,shrimp larvae and artificial feed,etc.Habitat layers of fry are transferred from upper and middle layers into middle and under layers in the water,and their behavior underwent horizontal swimming,cruising and feeding cruising around the pond,three types of swimming behavior.The lowest of specific growth rates of fry were at late larva stage（3.18%/d）and the highest at mid juvenile stage（13.31%/d）.The relationship between total length and day age or cumulative temperature could be fixed to the exponential function（y=aebx）.The relationship of pre-anal length or body height and total length could be described by allometric growth model（y=axb）.These growth showed two different stages indicated by inflexion points,which appeared at 16-17 d,total length 10.0 mm and 16-17 d,total length 10.5 mm,respectively.Before the inflection point,the growth of pre-anal length and body height were faster than total length（b1）,after the inflection point it was slower（b1）.It is recommended that the larvae of tawny puffer should be fed with Brachionus plicatilis（S-type）with 5-7 ind/mL at 4 days old,fry density should be reduced at 10-12 days old,fry should be transferred from indoor into pond outdoor at about 20 days old and divided to breed by sifting when fry can ingest artificial feed（35 days old）to improve the survival rate in tawny puffer fry rearing.