The Effects of Biodiesel and Crude Oil on the Foraging Behavior of Rusty Crayfish, Orconectes rusticus.

Abstract

Environmental pollutants, such as crude oil and other petroleum-based fuels, inhibit and limit an organism's ability to perceive a chemical stimulus. Despite the increased use of alternative fuels, such as biodiesel, there have been few studies investigating the impact of these chemicals on the behavior of aquatic organisms. The purpose of this study was to compare the sublethal effects of biodiesel and crude oil exposure on chemically mediated behaviors in a freshwater keystone species. Crayfish (Orconectes rusticus) were tested on their ability to respond appropriately to a positive chemical stimulus within a Y-maze choice paradigm. Behavior was quantified by measuring time spent finding an odor source, duration of time spent at the odor source, percentage of crayfish that found the odor source, and percentage of crayfish that chose the correct arm of the arena. Results indicated negative impacts of both biodiesel and crude oil on the ability of crayfish to locate the food source. However, there were no significant differences between behavioral performances when crayfish were exposed to crude oil compared with biodiesel. Thus, biodiesel and crude oil have equally negative effects on the chemosensory behavior of crayfish. These findings indicate that biodiesel has the potential to have similar negative ecological impacts as other fuel source toxins.