Amyloodiniosis in juvenile of Diplodus argenteus (SPARIDAE) maintained at different salinities

Abstract

This work reports the first occurrence of amyloodiniosis in silver porgy Diplodus argenteus and resistance of juvenile silver porgy to a wide range of salinities. The parasitism was diagnosed during a growth experiment conducted with 540 juveniles silver porgy with average weight of 0.1 ± 0.03 g and 19.0 ± 1.83 mm of total length, distributed in 18 tanks with a density of 0.33 ind L^-1 and fed commercial diet for 14 days. Six treatments, T1 to T6, in triplicate, corresponded to the salinities tested: 10, 15, 20, 25, 30 and 34 psu respectively. While the basic parameters of water quality remained within normal ranges for all treatments, mortality rates were significantly different, ranging from 0 to 100% at the end of the study. The results indicate that silver porgy tolerates different salinities, but it is highly susceptible to amyloodiniosis; Amyloodinium cf. ocellatum has its pathogenic action reduced in lower salinities.