DARK: AGE AND GROWTH OF PACIFIC HAKE 



62 

 60 

 58 

 56 



E 54 

 u 



""' 52 



I 



o 50 



z 

 tu 48 



_j 



46 

 §441- 



CD 



421- 

 40 

 38 

 361- 



(1958) 



(1964)/ <• 

 (1963) '/ 



(1956) 



— I— 

 3 



— 1 1 1 1 1 1 1 1 1 



5 6 7 8 9 10 II 12 13 



AGE ( years ) 



Figure 11. -Average fork lengths at various ages by year class (in parentheses) for Pacific hake taken off 



Washington, 1964-69. 



analysis. A sample of 10 was not attained in those 

 centimeter groups near the extremes of the length 

 distribution nor in those length groups where 10 

 samples were taken but not all otoliths were 

 readable. Fork lengths represented ranged from 

 11 to 68 cm. To facilitate the measuring all otoliths 

 were photographed and enlargements made so 

 that the prints were 16 times the size of the 

 otoliths. Measurements were taken directly from 

 each print. A midpoint was determined on the 

 photograph of each otolith by measuring the dis- 

 tance from the anterior edge to the posterior edge 

 of the first translucent zone and halving that 

 measurement (Figure 12). Measurements were 

 made from this midpoint to the anterior margin of 

 each annulus and to the anterior edge of the 

 otolith. When annuli were not clearly defined, 

 measurements were not made. 



The mean body length per centimeter of otolith 

 radius was computed and plotted in Figure 13. A 

 curve constructed from the individual observa- 

 tions (n = 370) is superimposed on the means. The 

 curve was constructed from a third degree 

 polynomial equation of the form Y = 18.78957 - 

 3.79065X + 0.67490Z^ - 0.01836X\ where Y = es- 

 timated body length and X = otolith radius. This 

 equation provided the best fit (smallest residual 

 sum of squares and mean square) of the several 

 functions examined (Table 5). The correlation 



Anterior edge 



7 th annulus 

 6th onnulus 

 5th annulus 

 4 th annulus 

 3rd annulus 



2 nd onnulus 

 I St onnulus 



Midpoint 



2nd year radius, etc. 

 1st year radius 



Figure 12.-Pacific hake otolith showing the calculated midpoint 

 and measurement intervals from the midpoint to the anterior 

 margins of successive annuli. 



349 



