Validation of daily increment formation and the effects of different temperatures and feeding regimes on short-term otolith growth in Australian smelt Retropinna semoni

Abstract –  To aid otolith interpretation of wild fish, we conducted a laboratory study using metalarval Australian smelt ( Retropinna semoni ) collected from the Murray River, to examine daily increment deposition and the effects of different temperatures and feeding regimes on otolith growth. Daily increment deposition was confirmed by comparing the number of increments from an oxytetracycline mark with the known number of days from marking. After holding fish at two temperature levels and three feeding rates, both food density and temperature were found to have a significant effect on otolith growth, with food density having the greatest influence. Overall trends in final lengths and condition of fish were well represented by recent otolith growth. The results of the experiment have implications for estimating growth histories and its relationship to various environmental conditions.