Estimation of a population's age distribution from its
length distribution based on von Bertalanffy's growth
curve, as described by Kell and Kell (2011)
Usage
age_slicing(fi, li = as.numeric(names(fi)), vb_params, age_limits, timing = 0.5)
Arguments
fi
A vector with the number of individuals per
length class.
li
A vector containing the length value for each
length class. If blank, will use
as.numeric(names(fi)).
vb_params
A named vector with the parameters of
the von Bertalanffy growth equation, Linf,
K and t0.
age_limits
A vector with two elements, containing
the lowest and highest age classes.
timing
Correction for the offset between the data
collection and recruitment. Defaults to 0.5, i.e.
half a year
Value
A vector containing the number of individuals in each age
class.
Details
Age distribution is calculated by using the inverse of the
von Bertalanffy growth curve, whose parameters must be
known. Limits for the minimum and maximum ages must also be
given.
References
Kell, L., Kell, A. (2011). A comparison of age slicing and
statistical age estimation for mediterranean swordfish
(Xiphias gladius). Collect. Vol. Sci. Pap. ICCAT.
66/4, 1522-1534