ssbpurec {FLCore}R Documentation

Method for calculating Spawning Stock Biomass per unit recruit

Description

For an FLStock-class object with the natural mortality, maturity and stock-weight information, this method calculates the SSB per unit recruit.

Usage

ssbpurec(object, ...)

Arguments

object An object of type FLStock-class.
... Extra arguments accepted by each implementation.

Details

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.

Value

An object of class FLQuant-class whose first dimension is of length one.

Note

Author(s)

FLR Team

References

See Also

FLStock-class

Examples

## Not run: 
data(ple4)
spur.ple4 <- ssbpurec(ple4,start=1957,end=1966,type='non-param',plusgroup=FALSE)
## End(Not run)

[Package FLCore version 1.4-4 Index]