TropFishR (version 1.6.1)

synLFQ8: Synthetic length-frequency data VIII with variable harvest rate

Description

Synthetic length-frequency data as generated by the function virtualPop2 from the fishdynr package (Taylor and Mildenberger, 2018). Can be used by ELEFAN, ELEFAN_SA, or ELEFAN_GA. The data is generated with the following von Bertalanffy growth parameters:

• K = 0.5 +/- 0.05 (CV)

• Linf = 80 +/- 0.05 (CV)

• C = 0.0

• ts = 0.0

• t_anchor 0.25 (Time when yearly recruitment pulse occurs; e.g. 0 = Jan 1, 0.25 = Apr 1, 0.5 = Jul 1, 0.75 = Oct 1; repro_wt = c(0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0))

Further settings include:

• Lmat.f = 40 (length at maturity)

• Lmat.m = 36 (length at maturity)

• L50 = 20 (length at 50% prob. of capture with trawl net (Lc))

• wqs = 4 (width between 25% and 75% prob. of capture quantiles; i.e. wqs = 0 is knife-edge selection)

• M = 0.7 (Natural mortality rate)

• harvest_rate = 1, 0.8, 0.4, 0.1 for years 2014, 2015, 2016, 2017, repsectively (fishing mortality rate)

The average biomass relative to the unfished biomass and the yield per recurit for the years, 2014, 2015, 2016, 2017 is 0.16, 0.21, 0.41, 0.75, and 0.4, 0.43, 0.24, 0.07, respectively. Biomass over Bmsy as estimated with a surplus production model is 0.51, 0.67, 1.27, 2.18. Lopt is 53.33 cm.

Usage

data(synLFQ8)

Format

A list of class lfq consisting of:

• stock Stock ID or name,

• dates dates of sampling times (class Date),

• midLengths midpoints of the length classes,

• catch matrix with catches/counts per length class (row) and sampling date (column),

• comment additional comments to this data set.

Examples

# NOT RUN {
data(synLFQ8)

# plot of length frequencies
plot(synLFQ8, Fname = "catch")

# plot of restructured length frequencies
synLFQ8 <- lfqRestructure(synLFQ8, MA = 11)
plot(synLFQ8, Fname = "rcounts")



# }