Mark and recapture

Bean Soya  Mug beans

Mark and Recapture Method Lab Objective:

 To learn the mark and recapture method of estimating population size. 

Time: This lab will take several days to complete. Part 1 will take approximately 30 minutes and Part 2 will take approximately 30 to 45 minutes on the first day and less than 30 minutes on each of the next 3 days.

 Materials: · 50 beans (30 white and 20 brown· Jar with lid · Nail polish 

Background Information: A researcher visits a study area and uses traps to capture a group of individuals alive. Each of these individuals is marked with a unique identifier (e.g., a numbered tag or band), and then is released unharmed back into the environment. The researcher then uses the Lincoln index to estimate the size of the population.

 Part 1

 Procedure: 

1. Take 30 white beans and 20 brown beans and put them in the jar. 

2. Shake the jar; without looking, remove 10 beans. 

3. Count the number of brown beans left in the jar and record in Data Table 1.

 4. Repeat step 3 until the data table is complete (10 times). 

5. Use the Lincoln index to estimate the population size for each trial. (Multiply the total num of brown beans in the jar (20) by the number of beans you removed each time (10); then, divide this number by the number of brown beans you “caught” for that trial.) 

6. Add up the population estimate column and then divide the total by 10 (the number of trials) to get your average population estimate. 

Formula:

 Lincoln Index

P = (N1 x N2)/ R 

P = total size of population 

N1 = size of first sample (all brown beans in jar) 

N2 = size of second sample (recapture: some will be brown and some won’t) 

R = number of brown individuals recaptured or “caught” each time 

Trial number           Number of Marked beans in sample        Population Estimate        

1

2

etc

See Document flie