The Mark-recapture Method

Question 1

When can the mark-recapture method be used?

Answer 1

In a closed population

Question 2

What is step 1 in the mark-recapture method?

Answer 2

1. A specific area is demarcated

Question 3

What is step 2 in the mark-recapture method?

Answer 3

2. A number of individuals are caught, counted and marked, they are known as the 1st sample

Question 4

What is step 3 in the mark-recapture method?

Answer 4

3. The marked individuals are released into the environment

Question 5

What is step 4 in the mark-recapture method?

Answer 5

4. Sufficient time must be allowed for the marked individuals to mix with the rest of the population

Question 6

What is step 5 in the mark-recapture method?

Answer 6

5. Another group of individuals is caught and counted and they are known as the 2nd sample

Question 7

What is step 6 in the mark-recapture method?

Answer 7

6. The number of MARKED individuals in the 2nd sample are counted

Question 8

What is the calculation for the mark-recapture method?

Answer 8

[number in 1st sample x number in 2nd sample] divided by [number in 2nd sample previously marked]

Question 9

What precaution must be taken when performing the mark-recapture method?

Answer 9

• must not harm the individual or affect its survival
• mark must not wash off or wear away
• must be no immigration or emigration out of the population
• no mortality between the mark and recapture times
• marking method must not make an individual more or less likely to be recaptured