Methods to compute total catch, landings, discards and stock biomass

Description

These methods compute the total catch, landings, discards and stock biomass from the quant-structured values in numbers and weight per individual. The calculation for discards, landings and stock involves the product of the landings/discards/stock in numbers (landings.n, discards.n or stock.n) by the individual weight-at-quant (landings.wt, discards.wt or stock.wt), as in

landings = landings.n * landings.wt

By selecting slot="catch", computeCatch can calculate in the same way the total catch from the catch-at-quant and weight in the catch. Those two values (in slots catch.n and catch.wt can also be calculated by specifying slot="n" and slot="wt" respectively. Calling computeCatch with option slot="all" will carry out the three calculations. In this case, the returned object will be of class FLQuants, with elements names catch, catch.n and catch.wt, which can then be passed directly to the catch<- replacement method.

Generic function

computeCatch(object, ...)

computeLandings(object, ...)

computeDiscards(object, ...)

computeStock(object, ...)

Method arguments

object :

an object of a class for which this method has been defined.

slot :

a character vector to select the calculation to perform in computeCatch. One of "n", "wt", "all" or "catch", the default value. The later will compute the total catch (for slot catch) from catch.n and catch.wt

na.rm :

a logical indicating whether NAs should be deleted from the sums. Defaults to TRUE.

Methods

signature(object=FLCatch) :

computation on an FLCatch object.

signature(object=FLStock) :

computation on an FLStock object.

signature(object=FLIndex) :

computation on an FLIndex object.

Author(s)

The FLR Team

See Also

FLComp

Examples

data(ple4)
summary(computeLandings(ple4))
landings(ple4) <- computeLandings(ple4)
catch(ple4) <- computeCatch(ple4, slot="all")