Model Identification

The model that includes harvesting is given by

We have considered the case when C is constant.

Let us now assume that C is not constant

C therefore varies.

The modelling question is C varies with respect to what?? What affects the fishing rate?

Thus

 

 

and

 

 

How do we combine these two variables. ? We use our rule that we keep it simple. The simplest forms are: C = k( f+P) or k(f-P) or kfP or kf/P or kP/f

 

Our new model is