224 



Fishen/ Bulletin 100(2) 



100 



75 



50 



25 



Females 



4 3 5 12 16 15 15 3236242228 33 ?1 ^ 3 5 



CT 



S Males 



I 100 



Q. 



75 



50 



W 



3 1 9 10 18 8 17 25 34 2522 24 22 2610 12 2 



25 



|y Ijir 



lllllllllllll 



200 400 600 800 



Total length (mm) 



1000 1200 



Figure 7 



Percentage frequency of occurrence of gonads at stages 

 I-II (D) and stages III-VIII (Dt in each sequential 

 50-mm class of female and male Glaucosoma hehrai- 

 cum caught between December and March. The logistic 

 curve has been fitted to the data for fish with gonads at 

 stages III-VIII. The sample size is given for each length 

 class. 



punctata by Hyndes et al. (1998). Using data from the low- 

 er west coast of Australia, Hyndes et al. (1998) estimated 

 the von Bertalanffy growth parameters, L, k, and f^, for 

 King George whiting to be 538 mm TL, 0.47/year, and 0.13 

 years, respectively, for females, and 500 mm TL, 0.53/year 

 and 0.16 years, respectively, for males. Although there are 

 no published studies on the growth of pink snapper and sil- 

 ver trevally in Western Australia, the growth of these two 

 species has been investigated in New Zealand by Francis 

 et al. ( 1992) and by James ( 1984) respectively. The param- 

 eters L , k, and t,^ were estimated to be 720 mm FL (fork 

 length), 0.106/year and -0.75 years, respectively, for pink 

 snapper, and i-anged from 436 to 448 mm FL, from 0.27 to 

 0.43/year and from -1.6 to -0.6 years, respectively, for silver 

 trevally Although the growth coefficient, k. for dhufish, i.e. 

 0. Ill/year, was similar to that for pink snapper, it was ap- 

 preciably less that that for both Iving George whiting and 



silver trevally. Dhufish had an asymptotic length ca. 35% 

 greater than that of pink snapper and approximately twice 

 those of King George whiting and silver trevally. 



The lengths of females at maturity have been reported 

 as ca. 350 mm FL for silver trevally (James, 1984) and 

 413 mm TL for King George whiting (Hyndes et al, 1998) 

 and have been estimated as 237 mm FL for pink snapper 

 (calculated from Crossland, 1977). Although maturity is 

 first achieved by the females of snapper and dhufish 

 at 30% of their respective asymptotic lengths, it is at- 

 tained by the females of King George whiting and silver 

 trevally at 75-80'7f of their asymptotic lengths. This find- 

 ing implies that the last two species have a higher repro- 

 ductive load sensu Gushing (1981). Thus, although these 

 four species reach maturity and begin to occupy promi- 



