- A parasite capable of wiping out species of fish in Europe,
notably salmon, trout and carp, has been discovered by scientists.
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- The infectious disease, a type of micro-organism called
a protist, is carried by the topmouth gudgeon and, though it leaves its
host fish unharmed, it kills other species by destroying internal organs.
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- The gudgeon is a small, grey type of minnow. Being the
most invasive fish in Europe, it could spread the parasite and cause a
drastic fall in the diversity of freshwater fish, according to the scientists.
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- Today, in the journal Nature, a team working in Dorset
for the Centre for Ecology and Hydrology, Winfrith, and the Centre for
the Environment, Fisheries & Aquaculture Science, Weymouth, describes
how the disease has already stopped the European sunbleak, an endangered
species of minnow, from spawning.
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- This could lead to its eventual extinction. Sunbleak
populations have declined sharply in the past 40 years, matching the rise
in numbers of the topmouth gudgeon, which has spread rapidly since its
introduction into Romanian ponds close to the Danube in the 1960s.
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- Dr Rodolphe Gozlan, lead author of the report, said:
"The new disease is already affecting other freshwater fish such as
the fathead minnow and may affect native UK fish species.
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- "This parasite could threaten commercial fisheries,
including salmon farms."
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- So far the team has found 24 populations of topmouth
gudgeon across England and Wales that threaten the rivers Kent, Yorkshire
Ouse, Trent, Thames, Medway, Itchen, Test and Severn with invasion.
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- The team is now assessing whether the parasite has played
a role in the decline of the following European species, which occurred
after introduction of topmouth gudgeon: rudd, crucian carp, brown bullhead,
bitterling and gudgeon.
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- © Copyright of Telegraph Group Limited 2005.
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- http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2005/06/23/
nfish23.xml&sSheet=/news/2005/06/23/ixhome.html
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