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Stealth parasite threatens European fish

23 June 2005

A new deadly disease, carried by an invasive fish species, is threatening European fish diversity according to a paper published in the journal Nature on 23 June 2005.

Lead author Rodolphe Gozlan from the Centre for Ecology & Hydrology (CEH) said, "We have found a parasite that may pose a severe threat to some freshwater fish species in Europe. This discovery has major biological implications and may have economic implications."

The scientists working for CEH and the Centre for the Environment, Fisheries & Aquaculture Science (CEFAS) have found an infectious disease carried by the topmouth gudgeon - the most invasive fish species in Europe. The disease stops the European sunbleak, an endangered species in mainland Europe (although not native to the UK), from spawning - leading to its rapid decline and possible eventual extinction.

The scientists blame the disease for the rapid demise of the sunbleak in parts of Europe following the spread of the Asian topmouth gudgeon. "The new disease is already affecting other freshwater fish such as the fathead minnow and may affect native UK fish species," added Dr Gozlan.

But the researchers, funded by the Natural Environment Research Council and Defra, found that the parasite does not harm the topmouth gudgeon.

Dr Gozlan said, "The topmouth gudgeon is a healthy host for this deadly parasite. This parasite could threaten commercial fisheries, including salmon farms."

The researchers believe the parasite is closely related to Rosette Agent, identified in the United States for the first time in 1986, which kills salmon and similar species, both farmed and wild. Work is in progress to determine any differences between the present parasite and Rosette Agent.

The scientists say more work is required to determine the extent of the threat to European fish diversity, but have observed that sunbleak populations have declined dramatically in the last forty years and the species is now on the European list of threatened freshwater fishes. This decline coincides with the rise in numbers of the topmouth gudgeon and its rapid spread throughout Europe since its introduction into Romanian ponds close to the river Danube in the 1960s.

Topmouth gudgeon have been recorded in several rivers and lakes in England and Wales.

Further information

Barnaby Smith
Centre for Ecology & Hydrology
Press Office
Tel: 07832 160960

NERC Press Office
Natural Environment Research Council
Polaris House, North Star Avenue
Swindon, SN2 1EU
Tel: 01793 411561
Mob: 07917 557215

Anne McClarnon
Centre for Environment, Fisheries & Aquaculture Science
Tel: 01502 524370

Notes

1. The paper, 'Disease threat to European fish' will be published in Nature on 23 June 2005.

2. Dr Rodolphe Gozlan is based at the Centre for Ecology & Hydrology at Winfrith in Dorset.

3. The work was carried out as a collaborative project between the Centre for Ecology & Hydrology and the Centre for Environment, Fisheries & Aquaculture Science. The study was funded by the Natural Environment Research Council and DEFRA

4. The Centre for Ecology & Hydrology (CEH) is the UK's leading research organisation for land and freshwater science. Its 500 scientists carry out research to improve our understanding of both the environment and the processes that underlie the Earth's support systems. It is one of the Natural Environment Research Council's research centres. CEH has 8 research sites within England, Scotland and Wales and an administrative headquarters based at Swindon.

5. NERC is one of the UK's research councils. It uses a budget of about £350m a year to fund and carry out impartial scientific research in the sciences of the environment. NERC trains the next generation of independent environmental scientists. It is addressing some of the key questions facing mankind such as global warming, renewable energy and sustainable economic development.

6. CEFAS is an internationally renowned scientific research and advisory establishment, based at Lowestoft since 1902. It also has laboratories at Burnham-on-Crouch and Weymouth, and a number of other facilities around the UK. It became an executive agency of the Department for Environment, Food and Rural Affairs in 1997. CEFAS undertakes work on fisheries management, environmental protection and aquaculture. It offers a wide range of research, advisory, consultancy, monitoring and training activities to government departments (UK and foreign, central and local), international agencies, commercial companies and aid organisations.

Press release: 28/05