JackKnifeDepl: Jacknife Removal Method Estimator
In KevinSee/SiteAbundances: Template

Description Usage Arguments Value Author(s) References Examples

A function to estimate abundance based on a removal (depletion) method. Particularly useful when the number of total passes is small (<5), the total catch is small (<30) and the capture probability is low (<0.4).

1	JackKnifeDepl(data, group = NULL, grouped = FALSE)

`data`	dataframe or matrix with three columns containing the counts from each pass.
`group`	factor describing which group that depletion comes from. If grouped==FALSE, not needed
`grouped`	logical. If FALSE, all sites are treated as having the same probability of capture. If TRUE, each group has a probability of capture estimated separately.

`N.hat`	- estimate of abundance
`N.hat.SE`	- standard error of the estimate of abundance. Based on number of passes and catch on final pass
`p.hat`	- estimate of the probability of capture

Kevin See, QCI, Seattle, WA

Hankin, D. and Mohr, M. (2001). Improved two-phase survey designs for estimation of fish abundance in small streams. Unpublished manuscript.

data(depl.data)
# pull out examples with three-pass depletion data
three.pass.data = subset(depl.data, n.pass==3, select=c('pass.1', 'pass.2', 'pass.3', 'stream.name'))
# estimate abundance, ungrouped data
JackKnifeDepl(three.pass.data[,1:3])

# estimate abundance, group data by stream name
JackKnifeDepl(three.pass.data[,1:3], group=three.pass.data$stream.name, grouped=TRUE)