Illegal anglers will be targeted over the Bank Holiday weekend in South Yorkshire.
Fisheries enforcement officers from the Environment Agency will be visiting lakes and river banks across the county to check rod licences.
They will be looking for people who are fishing illegally, without a licence – and have said those caught may face prosecution.
Between April and June this year, the Environment Agency’s officers checked 2,366 licences in Yorkshire.
A total of 145 offences were reported as a result of the checks and there were 51 successful prosecutions.
Joanne Kay, fisheries and biodiversity team leader at the Environment Agency, said: “Anyone who takes the chance of fishing without a licence is at risk of being penalised through the courts.
“Fines can run into hundreds of pounds, whereas a fishing licence costs just £27.”