568 



Fishery Bulletin 103(4) 



Inner-shelf reefs (n=147) 



 Orpheus Pandora " Havannah 



Mid-shelf reefs (n=273) 



• Bramble * Britomart * The Slashers 



x 



9 * * 



Oufer-shelf reefs (n=296) 



° Pith * Barnett Patches 



10 



Myrmidon 



4 6 



Age (years) 



10 



12 



05 075 1 125 15 175 



K 



115 



110 



105 



100 



95 



90 



65 



12 



Figure 5 



Von Bertalanffy growth curves for Acanthochromis polyacanthus collected from three 

 reefs within each distance stratum. 95% confidence ellipses are given for the parameters 

 K (growth coefficient) and L x (mean asymptotic length). 



shelf positions were similar and indicated that K val- 

 ues for A. polyacanthus converge at asymptotic sizes at 

 approximately the same rate of growth, irrespective of 

 proximity to the coast (Fig. 5 and Table 3). However, an 

 obvious trend for increased L , occurred with increasing 

 distance from the coast (inner shelf: -83 mm, mid-shelf: 

 -99 mm, outer shelf: -102 mm). The growth parameters 

 offish from The Slashers were more similar to those of 

 fish taken from the outer-shelf reefs than to those we 

 defined a priori as mid-shelf (Fig.6). The Slashers are 

 in fact much farther from the coast (85 km), as are Pith 



Reef (74 km) and Barnett Patches (63 km) on the outer 

 shelf, than the other two mid-shelf reefs (Britomart: 

 39 km. Bramble: 41 km) (Fig. 1, Table 1). 



Mortality 



Mortality rates for A. polyacanthus did not differ sig- 

 nificantly between replicate reefs within inner-shelf 

 (test for slopes df (2 19 „ F=0.982, P=0.39), mid-shelf (test 

 for slopes df (2 19l , F=1.334, P=0.29) or outer-shelf (test 

 for slopes df (219) , F=0.658, P=0.53) locations (Table 4). 



