The viviparous blenny (Zoarces viviparus) as a bioindicator of contaminant exposure: application of biomarkers of apoptosis and DNA damage

The viviparous blenny (Zoarces viviparus), also known as eelpout, is considered a suitable biomonitor for use in European estuarine and coastal waters. We have previously shown that Z. viviparus from the industrialised Tyne estuary (UK) display certain histopathologies (e.g., ovotestis and hepatic nuclear and cellular pleomorphism), which are associated with contaminant exposure [Mar. Environ. Res. 55 (2003) 137]. Furthermore, the prevalence of these pathologies was higher than in fish collected from a less contaminated reference site (the Alde estuary, UK). Here, tissue samples were collected from Z. viviparus from the Tyne and Alde estuaries (in the spring and autumn) and analysed for DNA adducts using the 32P-postlabelling assay and for histopathology. Z. viviparus caught from the Tyne during the spring (56.4 ± 18.5 adducts per 108 nucleotides) and autumn (63.1 ± 7.5 adducts per 108 nucleotides) exhibited patterns of DNA adducts which indicated exposure to a complex mixture of genotoxins. In contrast, levels of DNA adducts in Z. viviparus from Alde estuary were significantly lower during both sampling periods. Histopathological changes to the gonads included intersex (ovotestis) and germ cell apoptosis (detected via the TUNEL assay) in male fish captured from the Tyne estuary. Further studies on the use of germ cell apoptotic rate at different estuarine sites are required if it is to be used as a reproductive biomarker of contaminant exposure in male fish.