678 



Fishery Bulletin 100(4) 



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Figure 5 



Monthly average marginal increment ratio for male (TL<86 cm.) and female (T<102 cm) 

 smooth dogfish (error bars are standard error). 



agreement between the two readers was over 84% and the 

 percent agreement within one year was over 96% (Table 2). 

 Agreement within one year was high (over 90%) for all size 

 groups except the largest, where it dropped to 79% . 



The largest marginal increments were observed in ver- 

 tebrae from animals collected in March (Fig. 5). A large 

 drop in marginal width appears to occur in May indicating 

 that band formation most likely occurs during April. The 



marginal analysis was only conclusive for juvenile-size 

 animals (males less than 86 cm TL, females less than 

 102 cm TL). By the time these animals become mature, 

 their growth has slowed dramatically and the difference 

 between margin widths becomes very small, making it dif- 

 ficult to elucidate monthly changes in margin width. 



Von Bertalanffy growth parameters were calculated 

 separately for males and females because of the approxi- 



