Swimming performance of juvenile Florida pompano (Trachinotus carolinus) and Atlantic spadefish (Chaetodipterus faber) exposed to sublethal concentrations of ethylene glycol and methanol: individual and synergistic effects

Abstract

Recently, new technology has pushed petrochemical exploration into increasingly deeper water (>305 m) at increased risks to marine fauna. One risk is from chemical additives used to enhance deepwater production such as ethylene glycol and methanol which are used during the production and treatment to prevent the formation of gas hydrates in deepwater wells and pipelines. Juvenile Florida pompano (Trachinotus carolinus) were used in controlled experiments to test the effects of 3.0 % ethylene glycol (EG), 1.07 % methanol (MeOH) and a combination of the two chemicals(EG + MeOH) on swimming performance of individual fish. Swimming performance was evaluated by comparing differences in pre- and post-exposure critical swimming speeds (Ucrit) for each individual to quantify sublethal effects. The experimental protocol included identical fasting, exposure, acclimation, and swimming experience for each group and required 18 days for the Florida pompano experiment. In juvenile swimming performance tests, single exposure to ethylene glycol and the combination of ethylene glycol and methanol significantly reduced Ucrit by 14.2 % and 43.3 %, respectively. No detectable difference in Ucrit was found for Florida pompano exposed to methanol or for the controls. Juvenile Atlantic spadefish (Chaetodipterus faber) were used to test the single effects of 3.0 % ethylene glycol on swimming performance of individuals. For Atlantic spadefish, there was a 7.3 % reduction in Ucrit compared to pre-exposure swimming performance and a 18.4 % reduction compared to the controls. The reduced ability of pompano and spadefish to sustain high prolonged and burst performance levels could have affects an individuals ability to avoid predators and feed effectively.