Strategic Stage

The problem is an extremely large and complex one. There is no hope of solving it as it is. What we can do is settle for a simpler version of the problem and solve that. After we have gone through the solution process of the simpler problem we will be better placed to solve the bigger one.

REMEMBER

Always start simple and then become more complex. Never start complex.

A simpler problem would be:
Assuming that the population of cod in the North Sea is known an the beginning of the year, what would the population be at the end of the year?