Age and growth of the common carp, Cyprinus carpio, in the River Murray, Australia: validation, consistency of age interpretation, and growth models

The present study validates age estimates from a suite of calcified structures (scales, opercular bones and otoliths), assesses the consistency of age interpretations and evaluates growth models in common carp from the lower Murray River, Australia. Marginal increment analysis was used to validate annulus counts, with attention to the 'edge interpretation problem'. The formation of annuli occurred annually after pooling annulus groups, and in carp 4 and 5 years old. The regular alternation of opaque and translucent zones in opercular bones and whole otoliths of younger and older carp was also suggestive of annual periodicity. From systematic comparisons, the use of both opercular bones and whole otoliths in routine age determinations is recommended. Six growth models, including the von Bertalanffy growth function (VBGF) and five polynomial curves were tested to describe growth in length. A log-log quadratic function, by virtue of its precision, and the VBGF, with wider applicability and more biological realism, were chosen.Lorenzo Vilizzi, Keith F. Walke