mortalities, for example, mortality due to disease (Laevastu and Larkins I98I). 



Input, species specific, natural mortality (SM ) is assumed to increase as a 



linear function of starvation (SC.,) : 



N 



FISHING MORTALITY (FP„ , ) 



N ,k 



The fishing mortality has two components--a constant rate of mortality, FK , 

 and a density dependent component, FM . Before equilibrium, total fishing mortality 

 is simply set at twice the constant component (i.e. 2 x FK ) . This value corresponds 

 to the available data on fishing mortality. After equilibrium, total fishing 

 mortality is equal to the constant rate plus the density dependent component. 

 The form of this density dependence is currently represented by the following 

 equat i on : 



^N 

 FM., = FK. ■' ■' 



N N ' V„ 



FP, = FM^ . FK^ 



The division of the fishing mortality into two components allows the 

 consideration of the relatively constant components (e.g., bycatch and 

 artisinal fisheries) separately from the density dependent component (e.g., 

 management adjustments). This formula may be modified in future simulations to 

 incorporate species specific factors. 



CONSUMPTION BY APEX PREDATORS (SS) 



The food requirements of the apex predators are a function of their biomasses, 

 Monthly variations in the biomass, and therefore the food requirements, do occur, 

 but from year to year they are invariant. Consequently, their food requirements 

 are computed once at the beginning of the model. Together with the percentage 



