mean.lifespan {FLCore} | R Documentation

## Method for calculating mean lifespan, given the natural mortality

### Description

For an `FLBiol` object with the natural mortality-at-age present in the object.

### Usage

    mean.lifespan(x, ...)

### Arguments

`x` | An object of type `FLBiol-class`.
`...` | Extra arguments accepted by each implementation.

### Details

Using actuarial definitions for the expected life-span of a given species, for a given survival rate-at-age (natural mortality), we can compute the expected life-span, $ell_x$, of a species, from a given reference age $x$, using the following equation:

ell_x = sumlimits_{t=1}^{infty} exp(-sumlimits_{i=x}^{x+t}M_i)

.

The method accepts objects of class `FLbiol` of any particular dimension. If the object has a seasonal structure to the population dynamics, then we sum over all seasons to get the yearly survival rate.

### Value

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

### Author(s)

FLR Team

### See Also

`FLBiol-class`

### Examples

    ## Not run:
    data(ple4biol)
    lfs.ple4 <- mean.lifespan(ple4,ref.age=1)
    ## End(Not run)

[Package FLCore version 2.2 Index]