Studies on the structure, life cycle and behaviour or Sardinella brasiliensis (Steindachner, 1879), in the region between 22ºS and 28ºS, Brazil: 1. Morphology or the otoliths

Abstract

A total of 4751 pairs of otoliths of Sardinella brasiliensis was colected between 22ºlat S and 28º lat S along and offshore the Brazilian coast. These pairs were studied to ascertain whether otoliths can be used as a reliable character for the assessment of individual age and population characteristics. The morphology of the otoliths is discussed in detail. Both periodic and non periodic rings (Tr and TPN) are shown to occur. TR and TPN are related to events during the larval and juvenile stages. Well defined growth rings are also present and may be used as age indicators. Morphologic and morphometric characters, specially length of rostrum, lenght of anti-rostrum and weight are correlated with total length; the results confirm earlier studies by different methods that suggest that the species, in the region studied, is broken down into different groups imperfectly isolated from one another. In conclusion, the study of details of the otoliths of this species is an useful addition to others as a mean to separate the various groups. Spatial and temporal distribution of specimens with different types of otoliths suggeets a certain degree of mixture among groups through migration of individuals and partial overlapping in space.