To measure the population of lake trout in a 250-hectare lake, 400 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 200 lake trout that were caught, 50 had fin clips. Using the mark-recapture estimate, the lake trout population size could be closest to which of the following?
A) 200
B) 400
C) 1,600
D) 80,000

Question

Quizplus · Accepted Answer

The mark-recapture method assumes that the proportion of marked individuals in the second sample is representative of the entire population. Using the proportion of marked individuals (50/200) as an estimate of the proportion of marked individuals in the total population, we can set up a proportion:
400/X = 50/200
Cross-multiplying, we get:
X = 1,600
Therefore, the estimated population size of lake trout in the lake is 1,600.

To Measure the Population of Lake Trout in a 250-Hectare