Effect of varying dietary energy contents with two protein concentrations on growth and feed utilization of juvenile Zacco barbata.

Abstract

This study intends to assess the effect of water mass on the growth and nutritionalcondition of Japanese anchovy,Engraulis japonicus,larvae.The anchovy larvae werecollected from the southern East China Sea(SECS),upwelling water(UWW)and Kuroshio(KUR)off northeastern Taiwan on March 1996.Their somatic growth,otolith growth andRNA/DNA ratios of anchovy larvae were measured.The growth rate of body and otolith inlength were significantly greater in the SECS than in the UWW and KUR.The nutritionalconditions of anchovy larvae were expressed by RNA/DNA ratio and the width of last twootolith increments in this study.Larvae from the SECS showed better nutritional conditionthan from the KUR and UWW.The estimated daily protein growth rate and recent otolithgrowth were significantly higher in the SECS than the SECS and UWW.It is suggestedthat the higher primary production in the SECS and therefore resulted in faster growth andbetter nutritional condition of the anchovy larvae.