Calculates proportions-at-age and standard errors from an age-length key assuming a two-stage random sampling design.
Usage
alkprop(x)
Arguments
x
a data frame containing an age-length key (similar to Table 8.3 on page 307 of Quinn and Deriso (1999)).
The first column must contain the length intervals as single numeric labels (no ranges), the second column must
contain the number of sampl
Value
resultslist element containing a table of proportions, standard errors, and coefficients of variation
for each age class.
Details
If individual fish from catches are sampled randomly for lengths and then are further subsampled
for age structures, Quinn and Deriso (1999: pages 304-305) showed that the proportions of fish in each age class
and corresponding standard errors can be calculated assuming a two-stage random sampling design. See reference to Table 8.4,
page 308 in Quinn and Deriso.
References
Quinn, T. J. and R. B. Deriso. 1999. Quantitative Fish Dynamics. Oxford University Press, New York, New York. 542 pages