AN alien fish is threatening native aquatic life in the Millennium Coastal Park.
Environment Agency Wales is taking action to eradicate what it has said is a highly invasive, non-native fish population.
It is to apply a chemical that kills fish (piscicide) to two lakes at the Millennium Coastal Park in Llanelli, to eradicate the non-native population of topmouth gudgeon.
Whilst the chemical is toxic to fish, it is not toxic to people, mammals, birds and other wildlife.
Prior to this, the Agency will be partially draining the lakes and removing the native fish such as carp, tench, roach and rudd, before applying the chemical. These fish will then be returned when the operation is complete.
Topmouth gudgeon is a small freshwater fish from Asia, which was brought to Europe accidentally in the 1960s, through the importation of other fish.
It is a highly damaging species which often goes unnoticed due to its small size, but can rapidly populate ponds, lakes and streams.
It has the ability to dominate a habitat and food supply, often leading to a decline in numbers of native fish.
During the operation, some paths within the Millennium Coastal Park will be closed in order to allow the Agency safe access to the Lakes.
The Agency and Carmarthenshire Council are asking members of the public to adhere to these closures which will be in place for two weeks, from Monday, October 29.
Phil Morgan, from Environment Agency Wales said: "This is the first phase in a wider programme to remove a harmful, damaging invasive species from our waters in Wales.
"Species such as topmouth gudgeon should not be in our rivers and lakes. It's important that we do what we can now to remove them before they spread further and have a devastating impact on our native fish.
"The most common way this species spreads is by people illegally moving fish from infected waters. Such activities can also cause the spread of other fish diseases and parasites."
Carmarthenshire Council executive board member of leisure services, Councillor Meryl Gravell, said: "Whilst the nature of this cleanup operation may be inconvenient to park users it is necessary and we welcome the support and help of the Agency in resolving these issues.
"There are many advantages of the carrying out of this operation - as well as removing the invasive fish, the lakes will be cleared of weed making the fishery within the park a top attraction for anglers once more."
Anglers are advised to carefully check, clean, and dry their equipment after use to help prevent further spread of the species.
Following the removal of topmouth gudgeon at the two lakes at the Millennium Coastal Park, the Agency will implement a larger scale eradication programme at three of the larger lakes at the coastal park in the new year.
Millennium Coastal Park is one of 23 established populations of topmouth gudegon in England and Wales.