ESTIMATION OF GROWTH RATE IN ANIMALS 



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LENGTH AT TAGGING IN >/ t CM. UNITS 



Growth lines determined from marked shrimp, with estimates of Li and La,. 



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Figure 2 



In Walford's transformation the two important 

 points are L„ and Li. These are obtained where 

 Y=X and where A=0, respectively. 



L„ can be calculated readily from the fact I hat 



F=a+bAand when F=A',also Y=jzr h = L ^  (3) 



Where Li is being obtained from two or more 

 transformation lines, approximations can be 

 reached by using formula 1. 



When transformation lines can be obtained 

 from two or more successive time intervals, ap- 

 proximations to L„ and La can be obtained from 

 their respective means. 



As an example of this procedure, I am giving 

 here the processes followed in obtaining a growth 

 approximation from an experiment with marked 

 shrimp. 



As Walford (194G) has cautioned, a great many 

 specimens are required for an accurate approxi- 

 mation to a growth line. The experiment I cite 

 has very few specimens and cannot be regarded 

 as representing growth in shrimp (Penaeus seti- 

 ferus) . I use it only to demonstrate the technique. 

 As a matter of fact, because of the variability of 

 the data I believe that, in an example such as this, 



