军曹鱼仔鱼异速生长研究

Allometric growth of Rachycentron canadum larvae

【目的】了解军曹鱼(Rachycentron canadum)仔鱼早期发育过程中器官发育的优先性及不同发育阶段的生长速率,完善其发育过程的基础生物学资料,为军曹鱼的苗种培育和健康养殖提供理论依据。【方法】采用形态指标测量军曹鱼个体的全长、头长、吻长、口宽、眼径、头高、体高、躯干长、尾长、胸鳍长及尾鳍长等指标,然后结合回归方程拟合的方法对军曹鱼仔鱼早期异速生长模式进行系统研究,包括头部器官、游泳器官和躯干部的异速生长模式。【结果】军曹鱼仔鱼全长(y)与日龄(x)关系的回归方程为y=3.8912e0.0388x(R2=0.9623),即在军曹鱼正常摄食的情况下,其全长增加速率随日龄的增加呈逐渐上升趋势。随着军曹鱼仔鱼全长的增长,其口径增加速率越高,其中最小和最大口径对应的全长分别为4.087和6.351 mm。在军曹鱼的头部器官中,吻长、口宽和头高在仔鱼发育阶段表现为正异速生长,眼径则表现为等速生长;在躯干部中,头长和尾长在仔鱼发育阶段为正异速生长,体高为等速生长,躯干长为负异速生长;在游泳器官中,军曹鱼胸鳍在仔鱼发育阶段保持正异速生长,尾鳍则为负异速生长。【结论】军曹鱼仔鱼发育阶段优先发育游泳器官和摄食器官,以增强其追逐及捕食能力,为生长发育提供饵料保障,保证营养充足,适应外界环境,进而提高仔鱼存活率。

【Objective】The priority of organ development and growth rates at different development stages in the early development process of Rachycentron canadum larvae were studied.The basic biological data of the development process could be improved to provide theoretical basis for the breeding and healthy aquaculture of the R.canadum.【Method】The morphological indexes were used to measure R.canadum individual total length,head length,rostrum length,mouth width eye diameter,head height,body height,trunk length,tail length,pectoral length and tail fin length.Then early allometric growth model of R.canadum larvae was researched systematically combining with the regression equation of the fitting method.It included allometric growth of organs in the head,swimming organ and trunk.【Result】The regression equation of the relationship between the full length of R.canadum larvae and the age of day was y=3.8912e^0.0388x(R^2=0.9623),under the normal feeding condition of R.canadum,the growth rate of the full length increased gradually with the age of day.With the increase of the total length of R.canadum larvae,the increase rate of mouth gape was higher,and the corresponding length of the minimum and maximum mouth gapes were 4.087 and 6.351 mm respectively.As for the major head organs,rostrum length,mouth width and head height exhibited positive allometric growth in larval development stage.Eye diameter exhibited the constant speed growth.In the parts of the trunk,the head length and tail length presented positive allometric growth,body height exhibited the constant speed growth,and trunk length presented negative allometric growth.As for the swimming organs,the pectoral fin of the R.canadum kept positive allometric growth while caudal fin was in negative allometric growth.【Conclusion】In R.canadum larvae development stage,the priority is to develop swimming organs and feeding organs to enhance its pursuit and predation ability,ensure sufficient nutrition,adapt to the environment and improve the survival rate of the larvae.