# Population Decline

• Apr 16th 2014, 05:59 PM
awfulatmath
Population Decline
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
$P(t) = Po e^rt$ help solve the equation
• Apr 16th 2014, 06:15 PM
SlipEternal
Re: Population Decline
I don't see why you would need that, but I suppose you could try to fit that equation. All that is being asked is that at the beginning of 2012, 36% of the original 250 walleye are no longer in the lake. So, the number of fish in the lake is 250 minus the 36% of 250 = 250-0.36*250 = 250(1-0.36) = 250(0.64) = 64% of 250 = 160 walleye at the beginning of 2012.
• Apr 16th 2014, 06:22 PM
awfulatmath
Re: Population Decline
I guess I'm thinking to much about it, can I could use the same process to show the increase as well? Instead subtracting I add?
• Apr 16th 2014, 08:12 PM
SlipEternal
Re: Population Decline
Yes, that is correct. Unless it asks you about a population trend that it wants you to extrapolate, you don't need to use the population growth/decline formula.