Question

At a nearby lake, a couple of scientists want to approximately how many fish live in the lake. The scientists will use the Mark and Recapture Sampling method to estimate the size of the population.

First the scientists capture 35 fish in their nets. They Mark these fish with a tag, and release them back into the lake.
The scientists return the next day and Capture 30 more fish. 5 of these fish are the marked Recaptured fish from the previous day.

Use the Mark and Recapture equation to estimate the number of fish in the lake total.

Answer 1

The Mark and Recapture equation used to estimate the number of fish in the lake is:

N = (C1 x C2) / R

Where:

N = estimated population size

C1 = number of fish captured in the first sample

C2 = number of fish captured in the second sample

R = number of fish recaptured in the second sample

Given the information provided, we can plug in the numbers:

N = (35 x 30) / 5

N = (1050) / 5

N = 210

So the estimated population size of fish in the lake is 210.