Effect of rotifer size on survival and growth of the barber goby Elacatinus figaro during the initial phases of development

Abstract

During the larval rearing of marine fish, the highest mortality rates usually occur at the beginning of the exogenous feeding. The use of a live food of adequate size in the first week of larviculture may represent a significant increase in survival. To evaluate the effect of the size of rotifers on survival and growth rates of larvae of Elacatinus figaro, three treatments were tested in triplicate: Treatment Small (TS): rotifers with 102.2 ± 14.9 µm (lorica length; mean ± standard deviation, n = 10); Treatment Large (TL): rotifers with 177.0 ± 18.9 µm; Treatment Mixed (TM): rotifers with 146.0 ± 40.9 µm. Survival and growth rates were evaluated on the eighth day after hatching. Survival was significantly higher (P<0.05) in larvae from the TS (13.3 ± 2.3%, mean ± SD) and TM (9.3 ± 6.1%) in relation to larvae from TB (2.7 ± 2.3%). TS and TM did not differ significantly. No significant difference for the total length among TS (4.0 ± 0.5 mm), TL (4.0 ± 0.1 mm) and TM (3.6 ± 0.6 mm) was detected. The selection of rotifer strains of smaller size helps increasing the survival of E. figaro larvae. The size of rotifers for use in first feeding larvae of E. figaro should be within the range of 102.2 ± 14.9 and 146.0 ± 40.9 µm for lorica length and 59.4 ± 8.4 and 92.7 ± 29.8 µm for width.