bheq1 {fishmethods}R Documentation

Length-based Beverton-Holt Equilibrium Total Instantaneous Mortality Estimator

Description

The equilibrium Beverton-Holt estimator of instantaneous total mortality (Z) from length data with bootstrapped standard errors

Usage

bheq1(len, K = NULL, Linf = NULL, Lc = NULL, nboot = 100)

Arguments

len the vector of length data. Each row represents one record per individual fish.
K the growth coefficient from a von Bertalanffy growth model.
Linf the L-infinity coefficient from a von Bertalanffy growth model.
Lc the length at first capture.
nboot the number of bootstrap runs. Default=100.

Details

The standard Beverton-Holt equilibrium estimator of instantaneous total mortality (Z) from length data (page 365 in Quinn and Deriso (1999)) is calculated. The mean length for lengths >=Lc is calculated automatically. Missing data are removed prior to calculation. Estimates of standard error are made by bootstrapping length data >=Lc using package boot.

Value

Dataframe of length 1 containing mean length>=Lc, sample size>=Lc, Z estimate and standard error.

Author(s)

Gary A. Nelson, Massachusetts Division of Marine Fisheries gary.nelson@state.ma.us

References

Quinn, T. J. and R. B. Deriso. 1999. Quantitative Fish Dynamics. Oxford University Press, New York, New York. 542 pages

See Also

bheq2 bhnoneq

Examples

data(herring)
bheq1(herring[,1],K=0.54,Linf=339,Lc=240,nboot=200)

[Package fishmethods version 0.0-1 Index]