A population of lake Ontario salmon is being monitored A sam

A population of lake Ontario salmon is being monitored. A sample of 265 were tagged and released into the lake. Six months later, during spawning season when salmon begin to swim up streams to lay their eggs, 356 salmon were sampled from the lake and 22 had the original tag.

a. What is the estimated size of the salmon population? (please show all your work)

b. What assumptions about mark-recapture must be taken into consideration for this estimate to be valid.

Solution

No of Ontario Salmon tagged = 265

For total 356 fish that had tag = 22

Hence assuming the proportion for the whole population we have

a) Estimated size of salmon population = 265*356/22 = 4288.18

Near 4288

b) Assumptions made:

The sample taken represents the whole population.

The population will not migrate to nearby places.

There is no death or birth in 6 months affecting considerably the population.