Z_CPUE: Estimate Z from CPUE data

In tokami/TropFishR: Tropical Fisheries Analysis

Estimate Z from CPUE data

Description

Method to estimate the instantaneous total mortality rate (Z) from catch per unit of effort (CPUE) data according to standard, Heincke's, or Robson & Chapman's method.

Usage

Z_CPUE(param, method = "standard", omit_age1 = FALSE)

Arguments

param	a list consisting of following parameters: cohort: a vector with with a cohort label, age: a vector with ages, CPUE: a vector with CPUE values;
method	a character string indicating which assessment method should be used: "standard", "Heincke", or "RobsonChapman".
omit_age1	logical; if TRUE the first age group is omitted (Default FALSE).

Details

In Heincke's and RobsonChapman's method age groups older than 4 are lumped, because age groups older than 3 or 4 are said to be hard to seperate (Ricker, 1975). Sparre and Venema (1998) recommend to omit the first age group in case it is not fully exploited by the fishery.

Value

A list with input parameters and a Z value or matrix depending on the method.

References

Sparre, P., Venema, S.C., 1998. Introduction to tropical fish stock assessment. Part 1. Manual. FAO Fisheries Technical Paper, (306.1, Rev. 2). 407 p.

Sparre, P., Venema, S.C., 1999. Introduction to tropical fish stock assessment. Part 2. Excercises. FAO Fisheries Technical Paper, (306.2, Rev. 2). 94 p.

Ricker, W.E., 1975. Computation and interpretation of biological statistics of fish populations. Bull.Fish.Res.Board Can., (191):382 p.

Examples

# load data
data(synCPUE)

# run model with standard method
Z_CPUE(synCPUE, method = "standard")

# run model with Heincke's method
Z_CPUE(synCPUE, method = "Heincke")

# run model with Robson and Chapman's method
Z_CPUE(synCPUE, method = "RobsonChapman", omit_age1 = TRUE)

tokami/TropFishR documentation built on Feb. 29, 2024, 11 p.m.