Clissold ponds poisoned to eradicate deadly fish
PUBLISHED: 14:57 03 February 2015 | UPDATED: 15:10 03 February 2015
The ponds and moat at Clissold Park are to be poisoned this month as part of the removal of "one of the most threatening fish species in Europe" to eradicate the danger to other wildlife.
The ponds and moat at Clissold Park are to be poisoned this month as part of the removal of “one of the most threatening fish species in Europe” to eradicate the danger to other wildlife.
The topmouth gudgeon - banned from sale in England and Wales - is a member of the carp family, which the Environmental Agency (EA) cites as having a potentially “disastrous effect” on biodiversity and wildlife on a national level.
As part of a five-year nationwide programme to address problems caused by the fish, the invasive species will be removed humanely using an organic ‘piscicide’ called rotenone - a pesticide specifically designed to kill fish.
The EA said due to the risk of the topmouth gudgeon spreading, all fish from the ponds have to be removed, including native species.
According to the authority, rotenone does not affect mammals or birds, but may have a slight temporary effect on some invertebrates.
Though studies indicate the piscicide does not pose a human hazard, in its concentrated form it could act as an irritant.
Visitors to the park and their pets should take precautions and avoid contact with the moat or ponds until notified that it is safe.
While the EA carries out the work there will also be restricted area around the moats and ponds.
The silver and purple-scaled topmouth gudgeon can grow up to 10cm long and was originally imported from Asia as an ornamental fish.
They have since been found to breed rapidly and eat other aquatic invertebrates as well as the eggs and larvae of native fish.
The fish also out-compete native fish for food and habitat and can seriously reduce their numbers.
The topmouth gudgeon are thought to have been introduced to the ponds illegally through human interference.
Cllr Jonathan McShane, Cabinet member for health, social care and culture, said: “We fully support the Environment Agency in their removal work. The topmouth gudgeon poses a significant threat to the biodiversity of Clissold Park and, if left, could result in serious environmental problems on a national scale.
“This process is necessary to ensure the future health of not only Clissold Park’s waterways, but of rivers and ponds across the country.”