•13- 



Results and Limitations 



Complete utilization of all available prey can be obtained with a high value 

 for A or by iterating the procedure several times. Five iterations with A = 1.5 

 and B - 1.5 produced complete consumption of all prey biomasses when prey was 

 limiting. Although, superficially, this appears reasonable, it is apparent 

 that the feeding routine becomes highly dependent on the amount of each biomass 

 designated available for consumption which is difficult, if not impossible, 

 to quantify. In practice, one iteration with B - 1.5 and A - 1.5 was found 

 satisfactory, producing a stable equilibrium position with the equilibrium food 

 composition reflecting the input distribution. 



The approach is versatile enough to enable emphasis to be put on either the 

 input food composition table, or on the estimated prey availability. The level 

 of adjustment can be made specific to each predator biomass and used to investigate 

 the effects of a high or low prey selectivity by a predator. 



PRELIMINARY RESULTS FROM SKEBUB 



These results illustrate the output from a simulation on the sample data 

 given in Appendix Tables 1 to 6. They are presented here to provide the reader 

 with an illustration of the simulations in SKEBUB and are not intended to test 

 biological hypotheses. 



Many data result from a single run of SKEBUB. Laevastu and Bax (1982) 

 detail possible data outputs. Here we present mainly annual mean biomasses of 

 the various species groupings. There are two stages in the simulation. The 

 first stage produces an equilibrium situation given the input data. The 

 equilibrium biomass of a species group is that biomass which can be sustained 

 such that the growth of the biomass equals its mortalities. The equilibrium 

 situation may be considered an unnatural one, but it is a necessary starting 



