ssbpurec {FLCore} | R Documentation |
For an FLStock-class
object with the natural mortality, maturity and
stock-weight information, this method calculates the SSB per unit recruit.
ssbpurec(object, ...)
object |
An object of type FLStock-class . |
... |
Extra arguments accepted by each implementation. |
The SSB per unit recruit is a factor in stock-recruit functions, and yield-per-recruit
analyses, and can be computed either from regular FLStock
information
(maturity, natural mortality, stock weights), or from a simple regression
of the gradient of the equilibrium SSB-Recruits curve with zero fishing mortality.
Either are permitted, by using either 'non-param' or 'param' in the type
argument in the method.
For the non-parametric method, we can also supply arguments to tell the method when
to compute yearly-averaged values of natural mortality, weights and maturity, if
we believe that a certain subset of the years is clearly representative of virgin
conditions - for whatever reason - and this is done using the start and
end arguments and window
. The default behaviour is to just use the first
year in the object. Also, if we have a seasonal model, the user can supply
recruitment (recs) and spawning (spwns) seasons, so they can better
represent their stock's biology when computing the quantity - the default is that
both happen in season one.
An object of class FLQuant-class
whose first dimension is of length one.
FLR Team
## Not run: data(ple4) spur.ple4 <- ssbpurec(ple4,start=1957,end=1966,type='non-param',plusgroup=FALSE) ## End(Not run)