Schnabel Method for Estimating Population Size

The Schnabel Method for Estimating Population Size is used to estimate the size of a population by analyzing mark-recapture data. It is particularly useful when the population is closed (no immigration or emigration) and when marking and recapture are done correctly.

Input Parameters

Calculation Results

Estimated Population Size (N)

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Where:
N = (M * C) / R
M = Total number marked
C = Total number recaptured
R = Number marked in recapture

Schnabel Method for Estimating Population Size Calculator Usage Guide

Learn how to use the Schnabel Method for Estimating Population Size calculator and its working principles

How to Use the Calculator

  1. Enter the total number of individuals marked (M) during the first capture.
  2. Enter the total number of individuals recaptured (C) during the second capture.
  3. Enter the number of marked individuals recaptured (R) during the second capture.
  4. Click the "Calculate" button to estimate the population size (N).
  5. The estimated population size will be displayed along with the formula used.

Principle of the Schnabel Method

The Schnabel Method is based on the proportion of marked individuals recaptured in the second sample. The formula used is:

N = (M * C) / R

Where:

  • N is the estimated population size.
  • M is the total number of individuals marked in the first capture.
  • C is the total number of individuals recaptured in the second capture.
  • R is the number of marked individuals recaptured in the second capture.

This method assumes that the population is closed (no immigration, emigration, or births/deaths) and that marking does not affect the probability of recapture.