River Thames River Ray Yeast Estrogen Screen Picture credit: Tom Pottinger Roach Picture credit: Tom Pottinger 3-spined stickleback Picture credit: Richard Maunder Intersex stickleback testis Picture credit: Richard Maunder Electrofishing the River Ray Picture credit: Monika Jürgens THE EDCAT PROGRAMME: TESTING THE HYPOTHESIS THAT ENVIRONMENTAL OESTROGENS ARE A RISK TO FISH POPULATIONS Peter Matthiessen*, Jan Balaam #, Andrew Johnson*, Ioanna Katsiadaki #, Tom Pottinger*, Jim Readman ‡, John Sumpter †, and Charles Tyler § * Centre for Ecology and Hydrology (CEH), UK; # Centre for Environment, Fisheries and Aquaculture Science (Cefas), UK; ‡ Plymouth Marine Laboratory (PML), UK; † Brunel University, UK; § University of Exeter, UK For more information, please see the new EDCAT website: or contact Peter Matthiessen, the programme leader: EDCAT sponsors: UK Department for Environment, Fisheries and Rural Affairs (Defra); Environment Agency of England and Wales (EA); United Kingdom Water Industry Research Ltd (UKWIR) ABSTRACT This new programme seeks to test the hypothesis that the degree of oestrogen contamination in some UK rivers is a risk to fish populations. EDCAT (Endocrine Disruption in Catchments) is a multi-funder, multi-institute 6 year (Phases 1 and 2) programme which will:- 1. address this issue by studying a river downstream of an oestrogenic sewage discharge, before and after the levels of oestrogens are expected to be reduced by new treatment technology in study two aspects of fish populations – reproduction capabilities of intersex roach Rutilus rutilus in experimental tanks (breeding under competitive conditions with ‘normal’ fish and using DNA microsatellites to identify parentage in the offspring) - population status and dynamics of wild three-spined stickleback Gasterosteus aculeatus in the catchment and linking this to oestrogen-specific biomarkers and other pollutant markers 3. support these studies with oestrogen exposure measurements and modelling so that biological responses can be explained as fully as possible. INTRODUCTION Fish populations in many UK lowland rivers and estuaries are feminised (vitellogenin, ovotestis, feminised gonoducts, and/or feminised secondary sexual characteristics in males) There is a strong causal link with oestrogens and their mimics in sewage effluents In the lab, the sperm from wild intersex roach have a reduced ability to fertilise normal eggs Three-spined stickleback populations exposed as fry to environmentally-relevant levels of oestrogen show reduced reproductive output when allowed to free-breed as adults However, as yet there is no evidence that these effects are damaging breeding in wild fish, or compromising the stability of wild fish populations The EDCAT programme aims to look for such evidence using both experimental and field studies STUDY SITES We will study the River Ray in Wiltshire, UK, which receives oestrogenic sewage from a large sewage treatment works (Swindon STW), and make comparisons with a matched reference river (the River Ock, which drains a similar sized catchment with similar land-use) The River Ray was chosen because the Swindon STW is scheduled to start testing activated carbon technology in 2008 for removing oestrogens (as part of the Endocrine Disrupter Demonstration Programme). The Ray will therefore also act as its own control Several sites on the Ray, above and below the STW discharge, will be comprehensively sampled at least 4 times per year for the 3 years until the new treatment technology is commissioned, in order to establish baseline conditions It is planned to continue similar surveys after 2008 in order to monitor recovery STUDY PROGRAMME We have already developed predictive models of exposure to endocrine disrupters (EDs) in rivers, and EDCAT will refine these in order to provide a picture of expected seasonal changes The models will be validated with data on concentrations of EDs in the rivers, and on endocrine activity measured by in vitro assays such as the Yeast Estrogen and Androgen Screens (YES/YAS) Model outputs and direct exposure measurements will be used to guide the sampling programme for sticklebacks which will monitor population size and structure at several locations Sticklebacks will also be monitored for biomarker responses (e.g. vitellogenin and spiggin) to key EDs, as well as for indications of exposure to, and effects of, non-ED pollutants. This will allow correlations to be made between pollutant exposure and population status It is impractical to study roach reproduction in the field, so we will measure the reproductive ability of intersex fish experimentally in the laboratory. Groups of intersex males from the Ray (and elsewhere) and normal females will be allowed to freely breed in large tanks, and the parents of each offspring will be identified using micro-satellite genetic markers. This will reveal whether intersex fish are able to compete in normal breeding populations and contribute to the subsequent generation DISCUSSION AND CONCLUSIONS EDCAT is using modelling, experimental and observational approaches to assess population-level impacts of EDs because of the difficulty in deriving firm cause-effect conclusions from field studies alone It is recognised that the activated carbon treatment technology will probably filter out both EDs and non-EDs, hence the requirement to measure a wide range of pollutants and biomarkers EDCAT will compare data both with the reference river, and with the post-remediation situation, thus providing additional robustness This programme, if successful, will provide a more reliable assessment of the risks which some EDs pose to fish populations, and will also develop models which can be used to identify the STWs which pose the greatest risk to surface waters, thus allowing them to be prioritised for remediation POCIS water sampler Picture credit: Jan Balaam