Dumped goldfish endangering native carp in lake

Pet goldfish illegally dumped in a lake are endangering native fish species, the Environment Agency has warned.

The agency has been working with staff at Milton Country Park, near Cambridge, to develop one of its ponds into a haven for crucian carp, a protected native species in the UK.

However, it said 20 goldfish were recently released into Halls Pool at the park, putting “the entire stock [of carp] at risk of disease and viral infections”.

So far, agency staff have caught 15 goldfish while a child caught another, and they are hoping the remaining four can be removed from the lake.

Writing on Facebook, the Environment Agency said: “It puts the entire population of crucians at risk from hybridisation and loss of their unique DNA structure.

“This means unless we remove all of the goldfish we may have lost this lake for ever in terms of the true crucian carp population.”

The agency said the carp had “absolutely thrived in the weedy conditions of the lake” at Milton, to the extent “that we have been able to trap several hundred and move them to a second lake nearby to create another population of true crucians”.

It added: “We understand these [goldfish] would not have been released with any malice, but it is important to understand the risk of introducing ornamental fish to lakes and rivers.

“If your fish have outgrown your pond or tank then please try and rehome them sensibly to another fully enclosed ornamental pond or tank rather than releasing them into rivers and lakes.”

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