Summary
Estimates population size using the ratio of marked individuals recaptured in a second sample.
In depth
Lincoln index N = (M × n) / m, where M is marked in first sample, n total recaptured and m marked recaptured. Assumptions: no births, deaths or migration, marking doesn't affect survival, random mixing.
Marking must not harm or change behaviour. Mixing time is required. It works best for stable populations.
Remember: it estimates the population from the proportion of marked animals.
This method estimates the size of mobile animal populations. A sample of animals is captured, marked harmlessly, and released; after time to mix, a second sample is caught and the proportion of marked individuals recorded.
The Lincoln index gives population size N = (n1 x n2) / m, where n1 is the number first marked, n2 the second sample size and m the number of marked animals recaptured. Assumptions: no births, deaths or migration, marks do not fade or harm survival, and marked animals mix randomly and are equally likely to be caught again.
Example: 40 marked, second catch 50 with 10 marked gives N = 40 x 50 / 10 = 200.
Remember: violation of assumptions, such as trap-shy animals, biases the estimate.
Frequently asked questions
What is Mark-Release-Recapture?
Estimates population size using the ratio of marked individuals recaptured in a second sample.
Which area of biology covers Mark-Release-Recapture, and how advanced is it?
Mark-Release-Recapture is one of the 51 topics in Lab Methods & Biostatistics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Quadrats and Transects, Sampling, ELISA.
Can you give an example of Mark-Release-Recapture?
Estimating a snail population by painting shells.
What should I learn before Mark-Release-Recapture?
Work through the Beginner topics in Lab Methods & Biostatistics first, such as Scientific Method, Hypothesis, Variables, then return to Mark-Release-Recapture. Intermediate topics assume the Beginner vocabulary.
What topics are related to Mark-Release-Recapture?
The closest topics to Mark-Release-Recapture are Quadrats and Transects, Sampling, ELISA, ANOVA. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Mark-Release-Recapture?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Mark-Release-Recapture. To practise the whole of Lab Methods & Biostatistics, use the Lab Methods & Biostatistics quiz.
How is Mark-Release-Recapture different from Quadrats and Transects?
Mark-Release-Recapture: Estimates population size using the ratio of marked individuals recaptured in a second sample. Quadrats and Transects: Standard sampling tools used to estimate species abundance and distribution along gradients. Read both side by side and note what each one explains.
How should I study Mark-Release-Recapture step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Quadrats and Transects and explain the difference aloud. Finally, take the Lab Methods & Biostatistics quiz and come back to this page for any question you miss.