16/03/2006 - The Environment
Agency is taking steps to eradicate the
invasive topmouth gudgeon at a pond in North
Yorkshire. The fish is described as ‘high
risk’ because of its ability to reproduce
at up to four times the rate of other fish
and replace them. In order to protect the
unique ecology within the River Ouse catchment
Environment Agency staff will be applying
poison to Elm Hagg, a privately owned fishery
at Ampleforth, to kill off all topmouth
gudgeon.
The poison kills fish but is not toxic
to mammals or birds, and is called Rotenone.
It will be applied twice between now and
the end of March. Officers will be carefully
monitoring the site to ensure the safety
and success of the operation.
John Shannon, a fisheries team leader,
said: “Topmouth gudgeon have been described
as among the most damaging species to invade
western Europe, and could devastate the
ecology of our rivers.
“We’re working with English Nature, who
are also concerned about the dangers and
are helping to fund the work and giving
us consent under the Habitats Regulations.
We’re doing the work now because the water
temperatures are right and because the fish
are at a susceptible stage.
”We’ve looked carefully at the different
ways we could deal with this problem, and
the only way we can eradicate the species
from Elm Hagg is by poisoning it. All the
other options would have meant that the
fish could still be left to spawn and kill
off other fish, by competition for food
and habitat and by eating their eggs.
“We have carefully surveyed the watercourses
around Elm Hagg and have found no topmouth
gudgeon in those, so if we act now we can
prevent the further spread of this fish,
which would pose a significant threat to
the ecology of the Ouse catchment.”
The Environment Agency is taking the action
to poison the topmouth gudgeon because the
threat to the River Ouse catchment is so
great.
Topmouth gudgeon are a very successful
invasive species which out-compete most
other native fish species. This is because
they are small in size, can spawn on any
surface up to four times per year, have
a high tolerance of environmental conditions,
and eat the eggs of other fish. It is of
great importance that topmouth gudgeon do
not escape into any other waters.
