popN: popN calculates the proportional catch at age for catch...

In haddonm/datalowSA: A Package to Faciliate Application of Data poor Stock Assessments

popN calculates the proportional catch at age for catch curves

Description

popN calculates the expected proportional catch-at-age for use when using a multinomial likeihood to fit a catch curve that has been enhanced through the addition of a logistic selectivity curve. It generates the expected equilibrium relative numbers-at-age in the population and then uses the Baranov catch equation to generate the expected numbers-at-age in the catch, and hence to be expected in the catch curve. This approach requires three parameters while the classicCC uses only two parameters. This function is used within the function selectCC, that fits a catch curve enhanced with a selectivity curve so as to use the counts from all ages. It can also be used when plotting the outcome of a catch curve analysis.

Usage

popN(maxa, M, initF, select)

Arguments

maxa	the maximum age in the population and sample
M	the natural mortality estimate
initF	the fishing mortality to be tested
select	the selectivity of the fishery

Value

a vector of the expected proportional distribution of numbers-at-age

Examples

## Not run: 
M <-  0.6
age <- 0:9
counts <- c(3,4,501,2531,936,233,76,17,5,1)
pars <- c(lm50=2.5,delta=0.5,fcur=0.6)
pp <- popN(max(age),M,pars[3],logist(pars[1],pars[2],age))
round(cbind(age,counts/sum(counts),pp),5)

## End(Not run)

haddonm/datalowSA documentation built on Nov. 5, 2023, 6:40 p.m.