View source: R/Z_BevertonHolt.R
Z_BevertonHolt | R Documentation |
A method to estimate the instantaneous total mortality rate (Z) based on a method derived by Beverton and Holt (1956).
Z_BevertonHolt(param, catch_columns = NA, Lprime_tprime)
param |
a list consisting of following parameters:
|
catch_columns |
optional; in case catch is a matrix or data.frame, a number or vector
indicating which column(s) of the matrix should be analysed (Default: |
Lprime_tprime |
length or age prime, above which all fish are under full exploitation as mid length or age class. |
The first length group or age class within the list object midLengths
or
age
will be used as the Lprim or tprime (length of recruitment to fishery).
A list with the input parameters and following objects:
tmean or Lmean: mean age or length of fish,
tprime or Lprime: some age or length for which all fish of that length and longer are under full exploitation,
Z: total mortality.
Beverton R.J.H and S.J. Holt, 1956. A review of methods of estimating mortality rates in exploited fish populations, with special reference to sources of bias in catch sampling. Rapp.P.-v.Reun.CIEM, 140:67-83
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.
# based on length-frequency data
data(synLFQ2)
Z_BevertonHolt(synLFQ2, catch_columns = 2, Lprime_tprime = 47.5)
# based on age composition data
data(synCAA1)
Z_BevertonHolt(synCAA1, catch_columns = 3, Lprime_tprime = 2.5)
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