Age and growth of Pomadasys incisus 



857 



have little biological meaning (Schnute, 1981) and the 

 absence of parameters that take into account seasonal 

 changes in growth rate (Pauly, 1980; Moreau, 1987). Nev- 

 ertheless, the von Bertalanffy growth model has been used 

 extensively to describe the growth of grunts. The growth 

 model provides a simple description of growth which can 

 be compared between species and species groups (Booth, 

 1997). The special and the seasonal forms of the von Ber- 

 talanffy growth model were chosen for the present study 

 because they contain fewer parameters than the Schnute 

 growth model. 



Backcalculated lengths-at-age are in close agreement 

 with the length estimated from otoliths readings. The 

 results obtained with the backcalculation method are very 

 satisfactory because they show the consistency in the in- 

 terpretation of the sequence of growth increments of the 

 bastard grunt off the Canary Islands and reduce the effect 

 of size-selective sampling bias on the length estimates for 

 youngest fish in the sample (Campana, 2001). 



The growth parameters obtained are reasonable because 

 the theoretical maximal length value is higher than the 

 size of the largest fish sampled and the growth coefficient 



