Meeting Abstract
Crude oil causes both lethal, and a variety of sublethal effects on marine organisms, but the impact upon sensory function remains largely unexplored. The elasmobranch fishes often represent the upper trophic level predators in the marine ecosystem and thus rely upon the effective functioning of their sensory systems. Olfaction is used in prey, mate, and predator detection, and the olfactory epithelium is in direct contact with the seawater where it is exposed to environmental pollutants. The objective of this study was to test the effect of crude oil upon the olfactory sensitivity of a benthic marine predator, the Atlantic stingray, Dasyatis sabina. Stingrays were exposed to a 10% dilution crude oil solution, which replicates the concentration measured empirically in coastal areas following the Deepwater Horizon oil spill. An electro-olfactogram (EOG) technique was employed to quantify the response of the stingrays to five amino acids with different characteristics: Cysteine-polar, Alanine-non-polar, Phenylalanine-aromatic, Glutamic acid-acidic, and Arginine-basic. The magnitude of the EOG response for all amino acids was significantly depressed by 26% (Glutamic Acid) to 157% (Cysteine) in oil-exposed animals compared to control animals held in pristine water. Additionally, the EOG response onset was significantly slower, and the clearing time was protracted in oil-exposed individuals compared to control animals. These effects could ultimately lead to the stingray failing to detect prey, mates, or predators, which would detrimentally impact fitness. Further study is required to elucidate the mechanism responsible for the observed effects. This study is the first to quantify the effects of crude oil on the olfactory system of a marine predator.
