Bolz and Burns: Age and growth of larval Clupea harengus 



391 



Table 5 provides predicted ages of Atlantic herring 

 for given standard lengths with 70% and 95% confi- 

 dence limits, and Figure 5 shows the fitted growth 

 curve bracketed by its confidence limits. 



Otolith growth 



Because past studies have demonstrated a strong 

 relationship between mean otolith diameter (jam ) and 

 age (d) (Bolz and Lough, 1987), sagittal growth for 

 the seven seasons was analyzed and compared. The 

 extremely slow growth in otolith diameter during the 

 1976-77 season was dramatically different from the 

 other six years and resulted in a one-third smaller 



diameter at metamorphosis (Fig. 6). During 1988- 



89 and 1993-94, there appeared to be a decoupling 

 of somatic and otolith growth, such that 120-day-old 

 larvae were approximately 1.4-2.6 mm longer than 

 those in the four other recent field seasons and had 

 a smaller otolith diameter. 



Beginning with the 1989-90 season, the length of 

 the lapilli, as well as that of the sagittae, was mea- 

 sured. A plot of diameter of the lapillus versus age in 

 days showed an abrupt increase in its rate of growth 

 at approximately 2.5 months of age (Fig. 7). In 1989- 



90 and 1990-91 the point of flexion occurred at a 

 length of 29.1 mm SL when the larvae were 79 and 

 84 days old, respectively. Change in the growth of 



