Growth in eight species of tropical anchovy determined from primary otolith increments

Abstract

Growth in eight species of tropical anchovy from Townsville, North Queensland was analysed from counts of primary growth increments in the sagittal otolith. Experimental validation of growth increment periodicity in four species indicated that primary growth increments are deposited daily. Reparameterized von Bertalanffy growth equations were used to describe the relationship between length and age over the range of lengths aged in all species. Growth rate during the immature phase ranged from 0.4 to 0.7 mm d–1 with an average of 0.58 mm d–1. Longevity was estimated for four stolephorid anchovies and ranged from three to ten months. The short lifespan and high values of the growth constant, K, calculated for the smaller species of anchovy were consistent with other recent otolith-based studies on small tropical clupeoids. This paper reports the first study of large number of co-occurring closely related tropical anchovy species and evidence that growth increments are formed with a daily periodicity.