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The Research

Fresh from international acclaim for his research into the environmental threats posed to aquatic ecosystems, Professor Rudy Gozlan, an expert in invasive species, led an expedition to China to gather invaluable research samples of topmouth gudgeon, or pseudorasbora parva.

The topmouth gudgeon is extremely adaptable to different climates and has spread from its home in South East China to other parts of Asia, Europe and North America.

Outside of China, some topmouth gudgeons have been found to carry a parasite, known as the Rosette Agent - that is deadly to salmon, trout, carp and some endangered species – with a potentially detrimental impact to biodiversity and commercial fishing.

Live samples of the topmouth gudgeon have been brought back to the UK where BU’s ecologists will measure reproductive rates, parasite communities, size and other factors.

Professor Gozlan will use the data to identify the evolutionary shifts that have allowed the species to adapt to different climates, and the results translated into a climactic model that will enable scientists to estimate where the fish may spread to next.

The Academic

The dangers posed by the Rosette Agent parasite cannot be underestimated. This research established that, as the fastest growing invasive fish species in the world, the topmouth gudgeon’s ability to be a healthy carrier of this parasite meant it was, and still is, a significant risk to fish farming, particularly in light of the fact that it had caused a 90 per cent mortality rate amongst a North American salmon farm cohort. Subsequent research looked at the impact of the pathogen on native UK species, which proved to differ from the US strain. In Europe exercises to eradicate non-native species are rarely completed yet the Environment Agency in England & Wales has taken a different view, putting in place an eradication programme of topmouth gudgeon populations – and monitoring its efficiency going forward.

Professor Rudy Gozlan

The Student

Atlantic salmon in the UK are highly susceptible to the Rosette Agent parasite. The topmouth gudgeon is now established in England and Wales and is spreading north to Scotland. The parasite has been found to cause mortality in agricultural facilities in the USA and we now have a fish business that is carrying this parasite too. There are two things we need to do now, firstly to see how the Rosette Agent is affecting the wild Atlantic salmon population in the South West and secondly we need to check the potential for mortality in agricultural facilities in the North of England and Scotland.

Dr Demetra Andreou former PhD student, now lecturer in Environmental Sciences

The Impact

The topmouth gudgeon eradication programme put in place by the Environment Agency in England & Wales is still running successfully today and has led to the eradication of around 20 top mouth gudgeon populations. In addition, the existing legislation “The Prohibition of Keeping or Release of Live Fish (Specified Species) Order 1998, made under the Import of Live Fish (England and Wales) Act 1980 has been amended to include topmouth gudgeon. The topmouth gudgeon is now listed as a Category 5 risk species under the Importation of Live Fish Act (ILFA) which is the highest level of risk. The research has also served to raise public awareness around the world and topmouth gudgeon has been included as one of the top ten invasive species in Europe.

PhD student Gareth Davies, who led the Environment Agency eradication programme