Altered transcription levels of endocrine associated genes in two fisheries species collected from the Great Barrier Reef catchment and lagoon

• The Great Barrier Reef (GBR) is chronically exposed to agricultural pesticides.
• Estrogenic effects of such exposure were examined on two fisheries species.
• Altered transcription levels of liver vitellogenin (vtg) were found in both species.
• Levels of vtg were strongly associated with sugarcane run-off containing pesticides.
• These results are of concern for fishery resources exposed to agricultural run-off.

The Great Barrier Reef (GBR) is chronically exposed to agricultural run-off containing pesticides, many of which are known endocrine disrupting chemicals (EDCs). Here, we measure mRNA transcript abundance of two EDC biomarkers in wild populations of barramundi (Lates calcarifer) and coral trout (Plectropomus leopardus and Plectropomus maculatus). Transcription levels of liver vitellogenin (vtg) differed significantly in both species amongst sites with different exposures to agricultural run-off; brain aromatase (cyp19a1b) revealed some differences for barramundi only. Exposure to run-off from sugarcane that contains pesticides is a likely pathway given (i) significant associations between barramundi vtg transcription levels, catchment sugarcane land use, and river pesticide concentrations, and (ii) consistency between patterns of coral trout vtg transcription levels and pesticide distribution in the GBR lagoon. Given the potential consequences of such exposure for reproductive fitness and population dynamics, these results are cause for concern for the sustainability of fisheries resources downstream from agricultural land uses.