|Age determination by scale analysis in juvenile matrincha (Brycon cf. Melanopterus Müller & Troschel, Teleostei: Characoidei) a tropical characin from the Central Amazon|
Werder, U. (1983). Age determination by scale analysis in juvenile matrincha (Brycon cf. Melanopterus Müller & Troschel, Teleostei: Characoidei) a tropical characin from the Central Amazon. Amazoniana 7(4): 445-464
In: Amazoniana. Kommissions-Verlag Walter G. Mühlau: Kiel. ISSN 0065-6755, more
The experimental results prove the existence of a two-days' rhythm of sclerite formation in juvenile Matrincha (Brycon sp.). Identical scale patterns of wild-fish and pond-fish permit the application of a formula for age determination derived from pond experiments, also to fish from natural environments. The exactness of the formula for age determination can only be met by the otolith method. since the latter requires considerably more technical effort, and includes the risk of dealing with unreadable otoliths, the scale method presents itself as quite feasable, also for field work. All back-calculated spawning events coincide with increasing water-level, and high precipitations, thus confirming the fishermens' knowledge about interactions between 2 ecological factors and their importance for the onset of spawning.