L2F: L2F

In nikolaifish/bamExtras: Functions and Data in Support of Stock Assessments with the Beaufort Assessment Model (BAM)

L2F

Description

Approximate level of fishing mortality that achieves a given level of landings. This function is modified from code that was part of the BAM projections. The current function is intended for use prior to running run_proj to compute the F that matches specific values of landings. This is particularly useful if landings estimates corresponding to a year or years between the terminal year of the current stock assessment and the start year of new management is available.

Usage

L2F(L_tar, F_est, sel_L, sel_Z, M, N_a, wgt_L, control = list(iter.max = 500))

Arguments

L_tar	target landings value to match to the target fishing mortality value, F_tar. Must be in the same units as wgt_L.
F_est	initial guesses for the F that matches L_tar
sel_L	selectivity for landings
sel_Z	selectivity for total mortality
M	natural mortality rate, at age
N_a	vector of numbers of fish, at age, in population
wgt_L	vector of weight of fish, at age, in the landings
control	A list of control parameters passed to nlminb

Author(s)

Kyle Shertzer and Nikolai Klibansky

Examples

## Not run: 
spp <- rdat_Tilefish
endyr <- paste(spp$parms$endyr)
# Compute landings in weight for the terminal year
L_endyr_klb <- L_calc(F_a = spp$F.age[endyr,], Z_a = spp$Z.age[endyr,],
N_a = spp$N.age[endyr,], wgt_L = spp$a.series$gutwgt.wgted.L.klb)
L2F(L_tar=L_endyr_klb, F_est=sum(spp$F.age[endyr,]),sel_L = spp$sel.age$sel.v.wgted.L,
sel_Z = spp$sel.age$sel.v.wgted.tot,M = spp$a.series$M, N_a = spp$N.age[endyr,], wgt_L = spp$a.series$gutwgt.wgted.L.klb)

## End(Not run)

nikolaifish/bamExtras documentation built on July 21, 2023, 8:26 a.m.