Toxicity and Sublethal Effects of Methanol on Swimming Performance of Juvenile Florida Pompano

Abstract

Deepwater petroleum production requires that a number of additives, such as methanol, be transported offshore in large quantities, posing the risk of spills. Although these additives may not be highly toxic per se, it is important to evaluate and understand the risks to marine organisms, especially fishes that are often strongly associated with oil production facilities. We evaluated the toxicity and sublethal effects of methanol on the swimming performance of juvenile Florida pompano Trachinotus carolinus. A 24-h static exposure test identified the median lethal concentration as 1.28% (volume per volume) at 30 practical salinity units and 25°C. The mean critical swimming speed (U _crit) of juveniles (20.50 ± 4.59 g; mean ± SE) was evaluated before and after exposure to a 1.07% concentration and showed that U _crit was significantly reduced (P < 0.0002) from 90.10 ± 1.35 cm/s to 84.20 ± 1.36 cm/s in postexposure trials. After exposure and a 17-h recovery period in clean seawater, the mean 6.5% decline in performance of the treatment group contrasted sharply with a mean increase of 4.0% in the control group, indicating that conditioning, training effects, or both were significantly surpassed by the negative sublethal effects of methanol exposure.