624 



Fishery Bulletin 102(4) 



Esperance 



120 5 121 1215 122 122 5 123 123 5 124 



t 

 N 



1993 



• 



1994 



Figure 2 (continued) 



minimize variance. In terms of improving management 

 of the Sardinops fisheries in southwestern Australia, 

 we considered this approach appropriate because of the 

 relatively conservative exploitation rates that have been 

 adopted by the Management Advisory Committee. 



considered the following general relationship between 

 B sp DEPM and PPS holding over time: 



(B 



SP-DEPM 



i, = cx (PPS,)'- + a, + e r 



Hi 



Model selection 



The procedure used in the present study was to first 

 invoke a general model and then use the data to drive 

 a simplification process in order to avoid a specification 

 error. Thus, for each of the fishery regions, we first 



where A is common for all areas, a Q and a 2 are area 

 specific constants, and the error term e, is independent, 

 homoscedastic and normal with a mean of zero. This 

 model was chosen specifically in order to be amenable 

 to Taylor series expansion during the simplification 

 process. In satisfying dimensional and conservational 



