866 



Fishery Bulletin 97(4), 1999 



Table 4 



Results of fitting the von Bertalanffy growth equation of females and males of M. cephalus anci M. curenia. Entries include 

 parameters estimated and their estimated variance-covariance matrices (S). 



Mugil cephalus 



Males 



Females 



L =603.9 



k = 0.10536 



: 622.9 



/fe = 0.10736 <o = -2.669 



k 



tn 



3.1701E+02 



-1.1927E-01 

 0.4533E-04 



-1.3055E+00 n 

 0.5111E-03 =S„ 

 0.6360E-02 



1.8417E+02 



k 

 -0.5475E- 

 0.1642E- 



01 

 04 



-0.5870E+00 

 0.1810E-03 

 0.2221E-02 J 



1 



= S, 



Mugil curema 



Males 



Females 



: 411.8 



k = 0.1865 



454.6 



;fe = 0.1355 



k 



6.8027E+02 



-0.8253E+00 

 1.0212E-03 



-7.3708E+00 

 0.9428E-02 

 0.9296E-01 



8.7866E+02 



= S„ 



-0.6123E+00 

 0.4310E-03 



-8.3666E+00 

 0.6013E-02 

 0.8794E-01 



= S, 



The values of the parameters of the von Bertalanffy 

 growth equation for M. cephalus in different areas are 

 also shown in Table 6. The values of k are higher for 

 the coastal lagoons, whereas the L,^ values are lower 

 in relation to those obtained for the marine areas; all 

 these differences are important even in areas that are 

 very close (Kesteven, 1942; Thomson, 1951, 1963). 

 Thomson (1951) and Broadhead (1953) found impor- 



tant variations in M. cephalus populations in adjacent 

 estuaries; these differences can be explained because 

 of the populational density and abundance of food. On 

 the other hand, Oren ( 1981 ) showed that mugilids, be- 

 cause of the accessibility of the lagoons to the sea, can 

 emigrate to the sea at least once per year and mix with 

 other nearby populations. This exodus decreases the 

 amount of local variation in local growth rates. 



