Description Usage Arguments Details Value Author(s) Examples

A function that returns a vector containing the expected fraction of animals caught that were caught for the first time for each survey event. Model parameters are provided in the input vector. Survey information must be stored in specific-named global variables (see Details).

1 | ```
ExpectedFirstCapture(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:

- E
A double vector of size

`J`

quantifying the effort applied during each sampling event.- T
An integer vector of size

`J`

providing the day of each sampling event.- T.F
An integer indicating the first possible day of recruitment.

- T.L
An integer (>

`T.F`

) indicating the last possible day of recruitment.

A numeric vector of length `J`

.

Shane A. Richards ([email protected])

1 2 3 | ```
guess <- c(3.0, 3.0, 0.2, 0.0, 0.03, 0.1)
p.first <- ExpectedFirstCapture(guess)
plot(x = T, y = p.first, xlab = "Day", ylab = "Probability first time")
``` |

shanearichards/crrecruit documentation built on May 26, 2017, 7:01 a.m.

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