PARRISH: MARINE TROPHIC INTERACTIONS BY DYNAMIC SIMULATION 



proportionately to the abundance of the various 

 prey, but bias is allowed for known preferences or 

 differences in the ease with which various prey 

 can be taken. These features, together with the 

 basic structure of the age class model, allow that 

 predators and prey interacting with any species 

 may be different for different age classes of the 

 species or may change in their degree of impor- 

 tance. 



All the model species created for these simula- 

 tions are hypothetical. To avoid resorting to pure 

 fantasy and to get some consistency among cer- 

 tain species properties, each model fish species was 

 based on a real fish species (see Table 2). Real 

 species were selected which are sympatric, and in 

 fact, each of the predator/prey relationships 

 modeled has been reported in the literature in a 

 nonquantitative way. A major simplification in 



Table 2.-Values of parameters and of basic variables at standard equilibrium state as used in simulations. [Values shown in 



parentheses are alternate values used in some simulations.] 



•Values of variables at standard equilibrium state. 



703 



