Estimation of the proportion of 1 year old Anchovy in the November surveys : final results

In this document we explore the use of an objective method of estimating the annual proportion of 1 year old anchovy in the November surveys. This method involves estimating the length frequency distributions for both the 1 and 2+ year olds each year, and combining these using the estimated annual proportion-at-age 1 for that year to fit to the corresponding observed November survey length frequency. A number of alternative sources of information were also considered to ensure that the model predicted proportions-at-age-1 are realistic. The method provides a new time series of proportion at age-1 data, with associated SEs, to use in the assessment of South African anchovy.