Effects of naphthalene on metabolic rate and ammonia excretion of juvenile Florida pompano, Trachinotus carolinus

Bioassays were performed to determine the level of 96h-LC50 of naphthalene in Trachinotus carolinus and to investigate the effects of different concentrations of naphthalene, after acute (50-min and 24-h) and chronic (12-day) exposures, on the physiological parameters of the species. The 96h-LC50 at 24 °C was 2.83 ppm of naphthalene. Fish after acute exposures show a tendency to increase specific oxygen consumption by virtue of naphthalene concentrations. After chronic exposures, however, a decrease was observed at the highest concentration evidencing a narcotic effect of naphthalene. Ammonia excretion was reduced significantly, as compared to that of the controls, in all the exposed organisms. The O:N ratio indicated a tendency of using lipidic substrate to supply metabolic demands after long term exposition to naphthalene or to high concentrations of the pollutant. The effects caused by naphthalene were time and dose dependent for Florida pompanos.