bheq1 {fishmethods} | R Documentation |
The equilibrium Beverton-Holt estimator of instantaneous total mortality (Z) from length data with bootstrapped standard errors
bheq1(len, K = NULL, Linf = NULL, Lc = NULL, nboot = 100)
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. |
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
.
Dataframe of length 1 containing mean length>=Lc, sample size>=Lc, Z estimate and standard error.
Gary A. Nelson, Massachusetts Division of Marine Fisheries gary.nelson@state.ma.us
Quinn, T. J. and R. B. Deriso. 1999. Quantitative Fish Dynamics. Oxford University Press, New York, New York. 542 pages
data(herring) bheq1(herring[,1],K=0.54,Linf=339,Lc=240,nboot=200)