792 



Fishery Bulletin 98(4) 



(101) 



25 



November 





GN:76 (103) 



OL 



December 



GN = 77 



(109) 



o 



25p January 



ii 



o 25 r February 



E 



OL 



25 r 



March 



juBa, 



April 



May 



June 



SN = 41 



GN=13 (71) 

 RL=17 



SN= 8 



GN = S4 (86) 



July 



RL=2 (104) 



rrn GN = 102 



August GN = 69 



RL= 1 ('0) 



SN = 33 



GN = 37 (80) 



1994 



^'^ = 27 



GN=4 (34) 

 RL= 3 



(17) : 



SN = 29 



GN=14 (81) 

 RL = 38 



December 



GN = 96(101) 

 RL= 2 



(136) 



SN = 39 ,„,, 

 GN = 45 (84) 



1995 

 SN = 17 ,„„, 

 GN = 21 (3») 



GN = 22 (~^'' 



SN= 2 



GN = 96 (107) 



January 



I I n rfc' I 



February 



March SN=13 ,„„, 



RL = 16 (^^' 



April SN=4 



RL=,5 (19) 



— -i~wL „ 



100 200 300 400 500 100 200 300 400 500 



Total length (mm) 



Figure 5 



Lcngth-froqucncy histograms for the difTerenl year classes of Acanthopagriis biitcheri, with 

 data derived from samples of males and females collectively that were caught with seine and 

 gill nets in the upper Swan River Estuary between September 1993 and April 1995. Sample 

 sizes in each month are given for seine netting (SN). gill netting (GN) and rod and line (RL) 

 and in parenthesis for the total sample. 



stead estuaries. This feature was reflected in significantly 

 greater asymptotic lengths and lower k values for the 

 Moore River Estuary population than those derived for 

 fish in the latter two estuaries (Table 2, Figs. 6 and 7 1. 



The likelihood ratio test demonstrated that neither the 

 ages at length zero (/g) nor the growth coefficients (A') 

 in the von Bertalanffy gi-owth equations differed signifi- 

 cantly between female and male A. butchen in either the 



