Evaluating Sublethal Effects of Exposure to Petroleum Additives on Fishes Associated with Offshore Platforms: Respiration and Swimming Performance as Indices of Stress

The effects of chemical additives and mixtures employed in deepwater development and production of petroleum resources will be examined on the performance abilities of pelagic fishes. Information is lacking concerning the exposure of aquatic organisms to contaminants associated with petroleum extraction that can be lethal to a variety of aquatic organisms including fishes. While toxicological studies have established mortality rates for a variety of aquatic organisms including fishes, chronic exposure of fishes to dissolved contaminants may not cause them to die outright. They are likely to exhibit changes in performance that ultimately lead to reduced fitness. Ultimately, sublethal effects are less obvious but may have more significant environmental impacts through reduced fitness of exposed biota and potential transfer to humans through consumption of contaminated fishes. Knowledge in this field is sparse and the paucity of information may ultimately raise questions regarding environmental impacts.

Objectives:
The study will assess the influence of typical additives and mixtures of additives used in offshore operations on the ecological performance of three pelagic marine fishes that function as intermediate-level predators and prey in Louisiana marine waters. Target additives are methanol (MeOH), ethylene glycol (EG), and dodecyl benzene sulfonate (DBS). Proprietary mixtures of additives will also be evaluated. These chemicals will be evaluated by:

• conducting a comprehensive literature review to identify dose-response relationships for fishes;
• running and reviewing LC50 experiments on the target species;
• establishing a testing protocol and a dosing system to experimentally evaluate changes in critical swimming performance and scope for activity for the three fish species following exposure to the three common additives and a mixture of additives;
• establishing protocols for contaminating sea water with additives;
• evaluating the interactions between MeOH, EG, or DBS contaminated water and an environmental stressor (i.e. temperature) with respect to sublethal effects on swimming performance and scope of activity; and
• analyzing three ecologically important fishes, i.e., blue runner (Caranx crysos, Carangiade), creole fish (Paranthias furcifer, Serranidae), and vermilion snapper (Rhomboplites aurorubens, Lutjanidae), at the organismic level so that effects can be predicted at the individual, population, and community levels to exposure to additive contamination.