Ibahez Aguirre et al,: Growth analysis of Mugil cephalus and M. curema 



863 



distributions of joint probability, with three variables 

 and one common variance. 



The complete and eviscerated weights of 473 and 

 329 specimens of M. cephalus and M. curema , re- 

 spectively, were recorded for the study of growth by 

 weight. Weight data were recorded for each 20-mm 

 length interval and the average weight for each size 

 class was calculated. 



The function W= aL * was used to obtain the weight- 

 length relationship. Data for growth by length and 

 the weight-length relationship were used to obtain 

 the weight for each age. Growth by weight was ob- 

 tained by substituting L, and L^ by W, and W„, re- 

 spectively, obtained from the weight-length relation- 



ship in the von Bertalanffy equation. Taylor's equa- 

 tion (1958, 1960) was used to calculate age limit or 

 longevity (95% oiL^). 



Results 



Growth in length 



Mugil cephalus The values for L ., and k were very 

 similar ( Table 2 ). The method that provided the great- 

 est differences was that of Ford (1933) and Walford 

 (1946). This similarity was due to the obtention of 

 these constants; the t^ value determined by Gulland 



