Genotoxic, biochemical and behavioral effects of spilled oil in damselfish Stegastes fuscus.

In 2019, the Brazilian coast was contaminated by crude oil, affecting reef ecosystems and raising concerns about the toxicity of polycyclic aromatic hydrocarbons (PAHs) to reefs organisms. This study evaluated the ecotoxicological effects of the oil water accommodated fraction (WAF) on the reef fish Stegastes fuscus. Bile was analyzed by fixed fluorescence to detect PAHs metabolites. Biochemical biomarkers included ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), antioxidant defenses (catalase, superoxide dismutase and glutathione), and lipid peroxidation (LPO). Genotoxicity was assessed by the presence of micronuclei, nuclear abnormalities in erythrocytes, and total genomic damage. Agonistic, spontaneous swimming and scototaxis behaviors were analyzed. Total PAHs were quantified for 12% WAF and estimated for 3% WAF, resulting in concentrations of 201.5 e 50.4 ng ∑PAHs L-1, respectively. The results indicated a significant increase in the PAHs naphthalene, phenanthrene, pyrene, and benzo(a)pyrene in the bile of fish exposed to WAF. EROD activity was significantly increased in fish exposed to 201.5 ng ∑PAHs L-1, while the other biochemical parameters did not show significant changes. Micronucleus formation and total genomic damage increased in a dose-dependent manner, and the number of vacuolated nuclei was more frequent in fish exposed to the highest concentration. In the scototaxis test, fish exposed to 201.5 ng ∑PAHs L-1 spent less time in the dark region. After 96 h, agonistic behaviors were significantly more frequent in the control group, indicating that exposure to WAF may have impaired the fish's responses to threatening stimuli. These data indicate relevant genotoxic, biochemical, and behavioral effects in S. fuscus after exposure to crude oil.