Is there a formula to keep calculate a population that is declining? Here the problem

Suppose that at the beginning of 2011 the Michigan department of natural resources stocks a small inland lake with 250 walleye.

Over the course of the year is heavily fished and the population declines by 36% What is the population at the beginning of 2012?

Could the formula $\displaystyle P(t) = Po e^rt $ help solve the equation