Specific Merluccius otolith growth patterns related to phylogenetics and environmental factors

Abstract

A comparative morphological study was performed on the otolith growth patterns of 11 species of the genus Merluccius. The otolith growth pattern, based on the radius of the first eight growth increments (GI) from the otolith core, was determined from transverse sections of sagitta otoliths. The structure and periodicity of the GI were identified based on previous knowledge. Two cluster analyses were performed using GI width as a proxy for otolith growth. The first cluster analysis corresponded to the juvenile (immature) period of the fish including the mean width of the first four GI. The second analysis compared the mean width of the next four GI, i.e. those corresponding to mature fish. The results showed an important environmental influence in immature fish; while after maturation, the GI pattern was also related to an endogenous influence depending on the phylogenetic line.