calc_invALK: Classic ALK

In ALKr: Generate Age-Length Keys for fish populations

Description

Returns an inverse Age-Length Key calculated from a matrix with the count of individuals per age- and length-class, as described by Clark (1981), Bartoo and Parker (1983) and Hilborn and Walters (1992)

Usage

calc_invALK(x, fi)

Arguments

x	A matrix with i lines and j columns, where x[i, j] is the count of individuals of length i and age j.
fi	A vector of length i where fi[i] is the number of fish in the length-class j on the population from which x was sampled.

Value

A matrix with the probability of an individual of age j having length i, i.e. P(i|j).

References

Bartoo, N.W., Parker, K.R. (1983). Stochastic age-frequency estimation using the von Bertalanffy growth equation. Fishery Bulletin, 81/1, 91-96

Clark, W.G. (1981). Restricted Least-Squares Estimates of Age Composition from Length Composition. Canadian Journal of Fisheries and Aquatic Sciences, 38/3, 297-307. DOI: 10.1139/f81-041

Hilborn, R., Walters, C.J. (1992). Quantitative fisheries stock assessment: Choice, dynamics and uncertainty. Reviews in Fish Biology and Fisheries, 2/2, 177-178. DOI: 10.1007/BF00042883

Examples

data(hom)
calc_invALK(hom$otoliths[[1]], hom$F1992)

ALKr documentation built on May 30, 2017, 7:42 a.m.