Use of Otolith Length and Weight in Age Determination of Poor Cod (Trisopterus minutus Linn., 1758)


Abstract: Totally 189 poor cod (Trisopterus minutus Linn., 1758) specimens were collected by trawling in the central Aegean Sea between April 2001 and March 2002. The relationship of the otolith length and weight with the age of poor cod was investigated, as the age determination is relatively difficult by otolith readings. There was a linear relationship between the fish length (LT) and the otolith length (L_{o}), i.e. L_{o} = 0.421 LT + 1.659 (R^{2} = 0.998), a linear relationship between the fish age (T) and the otolith weight (W_{o}), i.e. W_{o} = 0.041 T - 0.030 (R^{2} = 0.994), and a power relationship between the otolith length (L_{o}) and the fish age (T), i.e. L_{o} = 13.663 (1 - e^{-0.271(t + 1.815)})(R^{2} = 0.997). The applicability of these relationships in age determination of poor cod was investigated and it was concluded that the relationship between the otolith weight and the fish age could be used in age determination of the species, with practical estimation, easy comparison, and low error rate.

Keywords: Poor cod, Trisopterus minutus, otolith, age

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