title: The effect of sublethal concentrations of the water-soluble fraction of crude oil on the chemosensory function of Caspian roach, Rutilus caspicus (YAKOVLEV, 1870).
abstract: The water-soluble fraction of crude oil is a complex and toxic mixture of hydrocarbons. Because aquatic organisms directly encounter it, the water-soluble fraction plays an important role in the toxicity of crude oil in aquatic environments. To determine whether fish are attracted to or avoid the water-soluble fraction, Caspian roaches (Rutilus caspicus) were exposed to different concentrations of the water-soluble fraction in a choice maze apparatus. The results showed that Caspian roaches can detect and avoid 2 mg/L of the water-soluble fraction. To study the effect of the water-soluble fraction on the olfactory function of fish, Caspian roaches were exposed to 3.2 mg/L and 16 mg/L of the water-soluble fraction for 96 h; afterward, exposed fish encountered food extract in a choice maze apparatus. The present study showed that the water-soluble fraction significantly impairs the olfactory function of roaches. To investigate the effect of olfactory system dysfunction on the feeding behavior of fish, Caspian roaches were exposed to 3.2 mg/L and 16 mg/L of the water-soluble fraction. After 4 d, 8 d, and 12 d of exposure, the feeding behavior toward the food extract was tested. The results showed that both 3.2 mg/L and 16 mg/L of the water-soluble fraction suppress the feeding behavior of Caspian roaches. The present study demonstrates that sublethal concentrations of crude oil's water-soluble fraction impair the olfactory function of fish and consequently suppress the feeding behavior.
authors.affiliation: Faculty of Biological Sciences, Shahid Beheshti University, General Campus, Tehran, Iran.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Lari
authors.affiliation: Faculty of Biological Sciences, Shahid Beheshti University, General Campus, Tehran, Iran.
authors.forename: Behrooz
authors.initials: B
authors.lastname: Abtahi
authors.affiliation: Department of Marine Living Science, Iranian National Institute for Oceanography and Atmospheric Science, Tehran, Iran.
authors.forename: Mehri Seyed
authors.initials: MS
authors.lastname: Hashtroudi
authors.affiliation: Department of Marine Biology, Faculty of Marine Sciences and Technology, Islamic Azad University of Iran, Tehran Sciences and Researches Branch, Tehran, Iran.
authors.forename: Effat
authors.initials: E
authors.lastname: Mohaddes
authors.affiliation: Program for Physiology and Neurobiology, Department of Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Kjell B
authors.initials: KB
authors.lastname: Døving
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects*; D006838:Hydrocarbons / Q000032:analysis / Q000737:chemistry; D010578:Petroleum / Q000032:analysis / Q000633:toxicity*; D014741:Video Recording; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D014874:Water Pollutants, Chemical; D014867:Water
keywords: Behavior; Caspian roach; Crude oil; Olfaction; Water-soluble fraction