FISHERY BULLETIN: VOL 75, NO. 1 



TABLE 3. — Computed mean weight per quarter at selected 

 lengths of male and female rex sole, using regression formulas 

 from Table 2. 



Sex 



Total 

 length 

 (cm) 



Computed mean weight (g) per quarter 1 

 I II III IV 



Male 



Female 



15 

 25 

 35 

 15 

 25 

 35 

 45 



11 



67 



221 



11 



64 



210 



506 



13 



71 



220 



13 



73 



231 



547 



13 



77 



256 



14 



83 



271 



655 



12 



68 



215 



12 



68 



231 



514 



'I = Jan-Mar.; II = Apr-June; III = July-Sept.; IV = Oct -Dec 



HOOr 



KX>0 



900 



o»800 



£ 700 



^ 600 



o 500 



O 



m 



z 400 



< 

 Id 

 2 300 



• MALES (N=950) 

 O FEMALES (N=II2I) 



^oo 



•cP 



200 

 I00 



d? 



.CP 



d?" 



Jp 



_l_ 



10 15 20 25 30 35 

 TOTAL LENGTH (Cm) 



40 45 50 



FIGURE 1. — Length-weight relationship for male and female rex 

 sole collected off central and northern Oregon, 1969-72. Body 

 weights obtained from an average of quarterly mean values. 



From these observations, we concluded that the 

 hyaline margin is deposited on otoliths during 

 each winter and spring for all sizes of rex sole. 

 Thus, these hyaline zones are interpreted as an- 

 nuli with a year's growth occurring between 

 successive hyaline margins. These results are 

 similar to those of Villadolid (1927) who found 

 northern California rex sole formed a scale an- 

 nulus in March through May. 



Age-Length Relationship 



After 3.5 yr of age, females were consistently 

 longer than males at a given age. Females also 

 attained an older age and longer length. Statistics 

 for both males and females followed the von 

 Bertalanffy growth curve, as a good fit was ob- 

 tained for most age groups (Figure 3, Table 4). 



I00r 



90 



80- 



~ 70 



w 60 



>- 

 o 

 z 50 



LU 



uj 40 

 or 



(13) 



(20) 



(18) 



30 

 20 



10- 



(93) 



(28) 



(32) 



S N D 

 1969 



(12) 



(13) 



(20) (16) 



MONTH 



M A M J J A 

 1970 



FIGURE 2. — Percent frequency of hyaline edges found on otoliths 

 of 265 rex sole (<27 cm TL) collected off northern Oregon, 

 September 1969-July 1970. Numbers in parentheses represent 

 sample size. 



40 r 



30 

 20 



10 







MALES 



I, =33.43 



( N = 257 ) 



[h 



-0.1778 (t-0.8551) 



1749 (t -0 5667)1 



6 8 10 12 



age (yr) 



14 



FIGURE 3. — Age-length relationship for male and female rex 

 sole collected off northern Oregon, September-October 1969 and 

 September 1971. 



The calculated length at infinity (Loo) of 33.43 

 cm for males was close to the computed mean 

 value of 29.33 cm (Table 4). For females theL^ of 



54 



