logisticSelect: logistic selection

In marchtaylor/fishdynr: Fisheries science related population dynamics models

Description

logisticSelect describes knife-edge selection where probability of capture 100% after a minimum defined size. Provides a rough estimate of trawl-type selectivity.

Usage

logisticSelect(Lt, L50, wqs)

Arguments

Lt	body size
L50	length at first capture (i.e. where prob. of capture equals 50%)
wqs	width of quartiles between 25% and 75% probability of capture

Examples

data(tilapia)
tilapia$selectFun="logisticSelect"
tilapia$L50 <- 20
WQS <- c(0, 3, 6)
COL <- rainbow(3)
for(i in seq(WQS)){
  tilapia$wqs <- WQS[i]
  res <- cohortSim(tilapia, t_incr=0.01)
  if(i == 1) plot(pcap ~ Lt, res, t="n")
  lines(pcap ~ Lt, res, col=COL[i])
}
legend("bottomright", 
       legend=paste(WQS, c(" ('knife-edge')", "", ""), sep=""), 
       col=COL, lty=1, 
       title="Width between 0.25 and 0.75 quantiles", bty="n"
)
lines(c(0,tilapia$L50,tilapia$L50), c(0.5,0.5,0), col=1, lty=2)
text(20,.5,bquote("L"[50]), pos=4, col=1, font=1)

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