The Environment Agency report that:

The case, taken by the Environment Agency, is the first of its kind in the region.

Non-native fish pose major risks to native fish and other wildlife; they can out-compete them for food and habitat, change the habitats they live in, spread disease and parasites and even eat  native fish. Keeping such fish without a licence is an offence under the Import of Live Fish (England and Wales) Act 1980. When licences are granted, they are subject to strict conditions.

Checks at Clawford Fishery, a commercial fishery owned by John and Wanda Ray, revealed the presence of two potentially invasive species; topmouth gudgeon and wels catfish, in several of the 17 lakes at the site. The lakes flow into the River Claw, connected to the River Tamar and the presence of these highly invasive fish posed a direct risk to the rivers valuable salmon populations.

Although only 3 – 4 inches long, the topmouth gudgeon, is one of the higest risk non-native species in Europe and consequently is not permitted in any waters. Wels catfish is Europe’s largest freshwater fish and can be a voracious predator. In fully-enclosed stillwaters, licences for keeping wels catfish may be issued, but in open sites connected to rivers, like Clawford, it poses a serious risk to other fish populations and cannot be kept.

Matt Brazier, for the Environment Agency said:

“Invasive non-native fish pose serious risks to our native species and habitats and are incredibly costly to the angling industry and the vital recreation and employment opportunities it provides. The Environment Agency is working hard with fishery owners and the fishing industry to prevent their spread and where high risk invasive fish are stocked illegally we will take appropriate action to ensure they are contained and removed”

Earlier this year the Agency launched a large scale operation to contain and remove topmouth gudgeon and wels catfish from Clawford Fishery. During the operation native fish stocks were rescued and held in quarantine while an organic ‘piscicide’ was applied to eradicate the invasive fish. The piscicide is designed to only remove fish and is not harmful to other wildlife. Once it had broken down, the native fish were returned and angling resumed at the site.

The fish removal and clean up operation at Clawford cost around £170,000 and lasted several weeks. The Agency will continue to monitor the site, but early indications are that the operation has been successful.

John and Wanda Ray, Clawford Fishery, Holsworthy, Devon, were fined a total of £4,950 and ordered to pay £30,000 costs by Barnstaple magistrates after pleading guilty to five offences under the Import of Live Fish (England and Wales) Act 1980.