"It out-competes our native fish" says Dave Mee, from the Environment Agency.
"Water becomes totally dominated by these small fish."
"They're small, they're a nuisance and they're not viable for anglers to fish for, so they're not a targeted species".
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Breezy overnight. It will become fairly cloudy as the night progresses.
It should turn cloudier through the early hours with some patchy drizzle and some hill fog too.
It will be a breezy day with variable amounts of cloud and some bright or sunny spells.