The Florida pompano, Trachinotus carolinus , a euryhaline Carangid species, found along the eastern Atlantic Ocean , is a prime candidate for aquaculture under low water salinity conditions . To test the effect of different salinities (10, 20 and 30 ppt)
on the gill histology , a total of 68 fish from 1 to 24 days post hatch were euthanized and fixed in 10% neutral buffered formalin. Then, they were processed for histology (4 μm cuts, H&E stains) and t he results were analyzed with SPSS 15.0 and WinEpi.
Pathological alterations in the secondary gill lamellae of the fish were observed, with hyperemia/haemorrhage, mucous cell hyperplasia and epithelial lifting (cell detachment) (Fig. 1) as the most frequent.
The number of gills with epithelial lifting was significantly higher ( by Pearson Chi Square, p<0.05) in fish reared at 10 ppt, with 45.45% of the sampled fish, (n = 22 ) compared to ≥20ppt (15.22%, n = 46 ) (Fi g. 2) , and this may constitute a risk factor for pre-metamorphosed pompano, and approximately 5 times more likely to suffer from g ill morphological alterations.
Our results show that rearing Florida pompano under 10ppt s alinity conditions can affect the gill’s histological integrity during early development, which can be frequently associated , according to other author’s, with respiratory and osmoregulatory distress, and a higher susceptibility to pathogen infections, resulting in health impairment and even mortality.