Gaughan et al.: Distribution of Sardinops sagax off southwestern Australia 



. 623 



Bremer Bay 



1993 



1994 



— ■'•■■ 



1999 



1204 



Figure 2 (continued) 



B SP . DEPM against PPS for the south coast locations 

 (Fig. 3). Because we wished to examine the relationship 

 between trends in DEPM-based estimates of B sp and 

 PPS with the aim of improving estimates of B sp , the 

 development of an appropriate model is described here 

 from first principles, followed by a selectivity analysis 



of error variance to choose the optimal estimator of B sp . 

 Given that we did not have a means of assessing the level 

 of accuracy of the "adjusted" estimates, and the aim was 

 therefore to improve consistency between data sets for 

 the purpose of enhancing the decision-making process, 

 our criteria in choosing an optimal estimator was to 



