DARK: AGE AND GROWTH OF PACIFIC HAKE 



2,000 r 



1,800 



1.600 



1,400 



1.200 





5 1,000 



800 



600 



400 



200 



o Female log W = -1.68944 + 2.69509 log L 

 + Mole logW=-l. 45990 + 2.55618 log L 



Female 



Male 



— I — 

 20 



— I — 

 30 



40 50 



LENGTH (cm) 



60 



70 



Figure 17.-Length-weight curves for male and female Pacific hake superimposed on 



mean body weights (n > 5). 



from 58 female hake from California ports, Best 

 (1963) estimated the exponent of the length- 

 weight equation to be 3.0668. On the chance that 

 the hake in commercial samples had lost weight 

 between capture and delivery through the loss of 

 body fluids, another pair of equations was fit to 

 less extensive length-weight data taken aboard 

 research vessels off Washington from freshly 

 caught specimens. Student's ^-test was used to test 

 the null hypothesis that regression slopes cal- 

 culated from research and commercial samples did 

 not differ significantly from 3. All tests were sig- 

 nificant at the 1% level (Table 9) and the 

 hypothesis was rejected. A possible explanation is 

 that because most specimens are in an immediate 

 postspawning state as they arrive off Washington 

 and Oregon, their weight relative to their length is 

 less than it might be later in the year. 



Growth in weight for males and females was 

 calculated from the length-weight equations 

 (Figure 18). These curves suggest that Pacific hake 

 gain weight at an increasing rate until they are 3 



yr old. After age 3 the rate of growth in weight 

 decreases and remains roughly constant until 

 death. By age 3, males have grown to approxima- 

 tely 50% of their total weight at 11 yr of age, 

 whereas females by age 3 have attained about 40% 

 of their total weight at 11 yr of age. The growth 

 rates are sex specific and the curves begin to 

 diverge noticeably between ages 3 and 4. At 11 yr 

 of age females weigh on the average about 200 g 



Table 9.— Results of f-tests to determine if slopes of length- 

 weight regressions calculated from commercial and research 

 samples differ significantly from 3. All comparisons were sig- 

 nificant at the 1% level. 



353 



