Investing populations

Mark-Release-Capture

Total Population size =

(no. caught in 1st sample* no. caught in 2nd sample) / No. marked in 2nd sample

• Capture a sample and mark them in some way 
• Release them back where you found them
• Wait a week, take a second sample
• Count how many of the second sample are marked
• Use the equation to estimate total population size 

Depends on some assumptions:

• That the marked sample has time to mix back in with the population
• That the marking hasn't affected the individual (survival chance) and…