convmort {fishmethods}

Conversion of Mortality Rates

Description

Convert instantaneous fishing mortality rate (F) to annual exploitation rate (mu) and vice versa for Type I and II fisheries.

Usage

convmort(value = NULL, fromto = 1, type = 2, M = NULL)

Arguments

value

mortality rate

fromto

conversion direction: 1=from F to mu; 2 = from mu to F. Default is 1.

type

type of fishery following Ricker (1975): 1=Type I; 2=Type II. Default is 2.

M

natural mortality rate (for Type II fishery)

Details

Equations 1.6 and 1.11 of Ricker (1975) are used.

Value

A vector of the same length as value containing the converted values.

Author(s)

Gary A. Nelson, Massachusetts Division of Marine Fisheries [e-mail]

References

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

Examples

convmort(0.3,fromto=1,type=2,M=0.15)