Age Determination of Microlepidotus brevipinnis (Steindachner, 1869) (Pisces: Haemulidae) in the Coast of Jalisco, Mexico, by Reading Otoliths and Scales

摘要

This study deals with age determination of the brassy grunt Microlepidotus brevipinnis by reading otoliths (sagittae) and scales which allowed the identification of 13 age groups. Growth of otoliths and scales is proportional to the growth of the fish. The time of formation of fast and slow growth bands in sagittae, as well as the time of ring formation in the scales is one year. The highest growth in length of this species takes place during the first year of life, in which the organism reaches 125.0 mm, this reduces natural mortality of the individuals by decreasing depredation. Growth in weight of this species is isometric. Sexual differentiation of the organisms is apparent after the age of two years and there were differences in the average length for each age in scales and otoliths for males and females. The age of other members of the Haemulidae family were compared with those obtained in the present study and M. brevipinnis reaches its oldest age in 13 years. It occupies a middle point (442.4 mm) in relation to the total lengths of other haemulids in the Mexican Pacific coast.