Age group and cohort
Length-frequency analysis of the 12 consecutive monthly samples collected for growth studies indicated a maximum of three age cohorts of males and females combined.
In samples collected on 30 May, 24 July and 18 August 2003 a single age class is evident, while on 21 June, 23 October, 22 November, and 23 December 2003, and 26 February, 28 March and 14 April 2004 two age groups are present (Figs 1 & 2).