A method to estimate the instantaneous total mortality rate (Z) based on a method derived by Beverton and Holt (1956).
a list consisting of following parameters:
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:
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
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.
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