World Aquaculture December 2019

52 DECEMBER 2019 • WORLD AQUACULTURE • WWW.WA S.ORG integrity of juvenile goldfish gills. The greater the concentration, the lower the integrity of the DNA. The results showed that time-response and dose-response curves could be obtained by using the alkaline unwinding assay to detect the degree of DNA single-strand breakage in juvenile goldfish gills after exposure to oil spill contaminants. The level of DNA damage can reflect the cumulative effect of genetic toxicity. Taking DNA damage as the biological indicator of the genetic toxicity of a pollutant has more advantages to show the nature of a pollutant’s impact than other biological indicators. Therefore, the DNA damage degree of juvenile goldfish gills could be used as an indicator to evaluate the long-term ecological environment of an estuary after an oil spill. DNA damage of liver tissue in adult shrimp ( Pandalus borealis ) exposed to an oil-water dispersion at 0.015, 0.060 and 0.250 mg/L was studied by Bachmann et al . (2010) using a continuous ow system. The alkaline unwinding assay was used to detect DNA damage after the first and fifth month of exposure and a concentration- and time-dependent increase in the level of DNA damage (lower F-ratio) was measured, even though exposure concentrations and the duration of exposure reflected chronic conditions. Thus, DNA damage can be used to assess the impact of an oil spill on the ecological environment, even if the oil spill occurred many months previous and at a low concentration of petroleum contaminants. The short-term effects of organic pollutant phenanthrene in the golden grey mullet Liza aurata , a fish species that is widely distributed in coastal waters, lagoons and estuaries, was assessed by Oliveira et al . (2007). The alkaline unwinding assay was used to determine DNA damage in mullet gills exposed to 0.1-2.7 μM phenanthrene for 16 h. DNA integrity was inversely related to pollutant concentration, indicating that phenanthrene could damage mullet gill DNA during short-term exposure. However, DNA damage in mullet exposed to 0.9 μM phenanthrene for 16 h was reduced by only about 12 percent compared to the control. Conclusion We used juvenile goldfish as an indicator organisms to monitor oil spill effects in an estuarine environment. Time-response and dose- response curves can be produced by using an alkaline unwinding assay to detect DNA damage of juvenile goldfish gills exposed to oil spill contaminants. DNA damage of juvenile goldfish gills can be an assessment criteria to evaluate the influence of a low-concentration oil spill to the environment in an estuary. Therefore, DNA damage in the gills of estuarine goldfish juveniles can be used as an indicator to reflect the security, risk, and quality of the estuarine ecological environment after an oil spill. Acknowledgments Yunan Yang thanks the State Oceanic Administration of the People’s Republic of China. This work was financially supported by the State Oceanic Administration of the People’s Republic of China Special Fund for Scientific Research in the Marine Public Welfare Industry (201305002). Notes Y.N. Yang*, H.J. Gong andMuhammad Aamir Bashir, School of Space and Environment, Beihang University, 37 rd Xueyuan Rd, Haidian District, P.O. Box 106, 100191 Beijing, PR China *Corresponding author. School of Space and Environment, Beihang University, 37 rd Xueyuan Rd, Haidian District, P.O. Box 106, 100191 Beijing, PR China Tel.: 86-10-13621289320 E-mail address: yangyn@buaa.edu.cn References Apraiz, I., M.P. Cajaraville and S. Cristobal. 2009. Peroxisomal proteomics: Biomonitoring in mussels after the Prestige’s oil spill. Marine Pollution Bulletin 58:1815-1826. Baussant, T., M. Ortiz-Zarragoitia and M.P. Cajaraville. 2011. 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