Growth of the king mackerel (Scomberomorus commerson) off the coast of Natal, South Africa- from length and age data

Growth parameter estimates for the king mackerel Scomberomorus commerson captured in the multi-species, multi-user fishery off Natal, South Africa, were obtained from a length- and an age-based method. Length composition analysis and age estimates derived from otolith readings yielded Von Bertalanffy growth parameters that adequately describe the growth of young king mackerel (less than 6 years). These growth parameters were based on the assumption that two opaque bands were laid down annually. Consistent with other recent age studies, growth of young king mackerel is very rapid, and the growth curves from both length composition analysis and otoliths reasonably predict the time at liberty for tagged individuals. The reproducibility of otolith readings was described by an index, the average per cent error, which is equal to 20.25% and is higher than than recorded in another study.