closedpop_time: A closed population function that calculates the length of...

In katherinekaplan/MPApopulationmodels: Population responses to marine protected areas (MPAs)

Description

A closed population function that calculates the length of time of the transient period after MPA implementation for a deterministic model This function calculates the ratio change in a fished poulation after a marine protected area is implemented assuming closed population method is from White et al. 2013 'transient responses of fished populations to marine reserve establishment published in conservation letters assumes a lambda of 1.0 in the MPA

Usage

closedpop_time(tf, maxage, Lmat, Lfish, M, Fi, Linf, k, a0, pW, qW)

Arguments

tf	the number of time step to run the population
maxage	max age of the species ie. number of age classes
Lmat	length at maturity
M	the natural mortality rate, if unknown generally use 0.2
Fi	the fishing mortality rate, F, find in stock assessment if don't have more localized estimate
Linf	asymptotic growth rate used in von-Bertallanfy growth equation, can find on fishbase
k	von-bertallanfy growth parameter estimate
a0	the age at length 0 used in the von-Bertallanfy growth equation
pW	weight length relationship parameter, same as a on fishbase.org but need to divide by 1000 to get in kg not grams
qW	weight length relationship parameter, same as b on fishbase.org

Value

transient_length is the length of time of the transient duration for the closed population

Examples

closedpop_time(M=0.2,Fi=0.14,Lfish=25,Linf=37.8,k=0.13,a0=-0.7,maxage=25,pW=9.37e-06,qW=3.172)
closed_time()

katherinekaplan/MPApopulationmodels documentation built on May 22, 2019, 8:51 p.m.