fitEcm: Fit Equal Capture Model (ECM)

Description

Fits the Equal Capture Model (ECM) to count data to obtain the MLE for population size

Usage

fitEcm(data, max.pop)

Arguments

data

A two-column data frame with the first column specifiying the capture class (i.e. individuals in class i were caught i times) and the second column specifying the number of individuals in each class

max.pop

The maximum population size

Value

model: The model specified
likelihood: The likelihood of the model
ml.pop.size: The maximum likelihood estimate for population size
cap.ind: The mean number of captures per individual
sampled.ind: The total number of individuals in the sample
sample.size: Total number of samples in the data set
max.pop: The maximum population size specified by max.pop

Details

The ECM model fit by this function assumes that all individuals are equally likely to be "captured".

The value is specified for max.pop is not likely to matter as long as it is much greater than the maximum likelihood estimate for population size.

Note that if the data contains only singletons, the data is not informative and the maximum likelihood estimate for population size will be equal to max.pop

References

Miller C. R., P. Joyce and L.P. Waits. 2005. A new method for estimating the size of small populations from genetic mark-recapture data. Molecular Ecology 14:1991-2005.

Examples

Run this code

## Simulate data under Equal Capture Model

data <- simEcm(n=40, s=150)

## Fit Equal Capture Model to Data

res <- fitEcm(data=data, max.pop=200)

res

Run the code above in your browser using DataLab