Description Usage Arguments Details Value Author(s) Examples
A function that returns a vector containing the probabilities a randomly chosen animal will be caught during each survey event. Model parameters are provided in the input vector. Survey information must be stored in specific-named global variables (see Details).
1 | ExpectedCapture(params)
|
params |
A vector containing six parameter values (see Details). |
The input params
contains the following values:
[tbar] The day when recruitment peaks.
[sigma] The spread in recruitment (days). Approximately 95% of recruitments occur during days [tbar - 2*sigma, tbar + 2*sigma].
[alpha0] Baseline catch rate (per unit effort).
[alpha1] Age-dependence in catch rate.
[beta0] Base-line mortality rate (per day).
[beta1] Age-dependence in mortality rate.
Recruitment is described by a Guassian peak centred on day tbar
with spread characterised by sigma
. Per-capita catch rate is given by: alpha0*exp(alpha1*age)
, where age
is the days since recruitment. Per-capita mortality rate is given by: beta0*exp(beta1*age)
.
Suppose the survey involves the capture of animals over J
sampling events. The data must be stored and summarised by the following R-variables:
A double vector of size J
quantifying the effort applied during each sampling event.
An integer vector of size J
providing the day of each sampling event.
An integer indicating the first possible day of recruitment.
An integer (> T.F
) indicating the last possible day of recruitment.
A numeric vector of length J
.
Shane A. Richards (shane.richards@csiro.au)
1 2 3 | guess <- c(3.0, 3.0, 0.2, 0.0, 0.03, 0.1)
p.detect <- ExpectedCapture(guess)
plot(x = T, y = p.detect, xlab = "Day", ylab = "Probability caught")
|
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