srrBH: Stock-recruitment relationship (Beverton-Holt type)

In marchtaylor/fishdynr: Fisheries science related population dynamics models

Description

srrBH describes stock-recruitment relationship as the number of recruits resulting from a given spawning biomass.

Usage

srrBH(rmax = 1000, beta = 500, SB = 500)

Arguments

rmax	maximum recruitment level
beta	parameter describing steepness of relationship. Specifically, beta describes the point where the number of spawned eggs results in half the maximum number of recruits, rmax
SB	spawning biomass of the adult population

Value

Number of recruited individuals

References

Beverton, R. J., Holt, S. J., 1957. On the dynamics of exploited fish populations

Examples

SB <- seq(0,1e11,,100)
rmax = 2e8
beta = 1e10
Nrecr <- srrBH(rmax, beta, SB)
plot(SB, Nrecr, t="l", ylim=c(0, rmax))
abline(h=rmax, lty=2, col=8)
lines(x=c(0, beta, beta), y=c(rmax/2, rmax/2, 0), lty=2, col=8)
text(x=0, y=rmax*0.95, labels="rmax", col=8, pos=4)
text(x=beta, y=rmax/2, labels="rmax/2", pos=4, col=8)
text(x=beta, y=0, labels="beta", pos=4, col=8)

marchtaylor/fishdynr documentation built on May 21, 2019, 11:27 a.m.