Reconhecimento de técnicas para identificação de anéis etários dos centros vertebrais da dourada (brachypiatystoma flavicans, castelneu, 1985)

Abstract

The sea bream (Brachyplatystoma flavicans, Pimelodidae) has a wide distribution in the Amazon and Orinoco river basins and represents one of the most important species for artisanal fisheries in the Amazon. The objective of this study is to establish patterns of age-ring recognition of the vertebral centers of the gilthead bream and relate them to fish meristics. Collections were carried out in the Amazon estuary during the 1996 dry season, the 1997 rainy season, and the 1997 dry season, respectively. A total of 1,215 gilthead sea bream were collected over this period. 900 vertebrae were extracted and weight, length and sex measurements were obtained. The sharpness, intensity, repetition of the rings, and the shape of their design were criteria used to examine the age structures in the vertebrae. This criterion helped select 653 vertebrae, whose concentric and complete rings were counted and measured. All vertebrae were analyzed more than once. The expression defining the relationship between fish length and vertebral radius is: Length = 116.0461 + 83.9793 * RM (n=653,P<0.01,r-=0.93). The biggest problem is still recognizing the first ring in the larger individuals, because in the smaller specimens this first ray (RI) measured approximately 0.5mm away from the vertebral core and in the larger ones from 0.8 to 1.0mm, indicating that the first ring in these individuals is being confused with the second or third ring of the vertebra.