Swimming Performance of Juvenile Florida Pompano Exposed to Ethylene Glycol

Abstract

Exposure to ethylene glycol, an additive in petroleum production, may not be immediately lethal to fishes but does affect swimming performance. All life history stages of Florida pompano Trachinotus carolinus are at risk of exposure from spills in the coastal and deep waters of the northern Gulf of Mexico. Toxicity tests on juvenile fish and subsequent probit analysis identified the median lethal concentration (LC50) as 5.63% (volume per volume) at 30 practical salinity units and 25°C. Behavioral observations of treatment and control groups during 24-h exposure and 15-h recovery trials showed that 2.1% ethylene glycol was the lowest concentration at which individuals displayed lethargic behavior relative to controls after 24 h. Fish exposed to concentrations of 3.1% or less became lethargic or distressed relative to controls but showed signs of recovery after 15 h in clean seawater. The mean (±SE) critical swimming speed (U _crit) of juveniles (23.1 ± 4.73 g) was evaluated before and after exposure to a 3.0% concentration. The mean U _crit declined significantly (P < 0.0002) from 95.9 ± 2.37 cm/s in preexposure trials to 83.0 ± 3.45 cm/s in postexposure trials. Exposure did not impact all individuals to the same degree, and smaller fish experienced a greater percentage decrease in swimming performance (%R) than did larger individuals (%R = −53.5 + (1.7 × body mass); R ² = 0.3148, df = 13, P < 0.0295).