Abstract

In this study, we investigated whether otolith weight can be used to estimate fish age with the same level of accuracy as that of the traditional annuli counting technique in a commercially important species such as haddock (Melanogrammus aeglefinus). Results indicate that this method is highly effective for young fish (around 97% correct classification), whereas its powers of prediction decrease with the increasing age of the fish. For older fish, the otolith weight cannot be an accurate estimator of fish age if the weight overlap between the different age classes is too large. Nevertheless, the otolith weight technique is strictly dependent on correct age determination through the counting of annuli of those individuals used in the calibration. Hence, an increase in the accuracy of ageing obviously determines an increase of the power of otolith weight to estimate fish age. Therefore, we suggest that otolith weight could represent a routine technique for determination of the age structure of haddock populations. This technique has the merit to be objective, fast, 100% repeatable and has the same level of accuracy as that of annuli counting.

Published in

Journal of Applied Ichthyology
2004, volume: 20, number: 6, pages: 470-475
Publisher: BLACKWELL VERLAG GMBH

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