Environment chiefs have reminded anglers the ‘close season’ for coarse fish in rivers is now in effect - and they can expect to be prosecuted if they flout the ban.
The close season prevents fishing for coarse fish, like barbel and chub, for three months (March 15 to June 15) to give the fish a chance to breed.
The ban applies to all rivers, streams and drains in England but does not apply to most still-waters and canals.
Despite this, popular still-water sites near Retford - the lake at Clumber Park and parts of the Chesterfield Canal - are part of the close season, as are Misson Line Bank, Thoresby Lake and Welbeck Lake.
On Chesterfield Canal the closed season is between Whit Sunday Pie Lock and Clayworth with the rest of the canal being open.
During the close season Environment Agency enforcement offices along with the Angling Trust&apos;s voluntary water bailiffs will be out on rivers and streams making sure people are observing the close season.
They will also be checking lakes and ponds to make sure people who are fishing have a valid rod licence.
Anyone fishing without a licence can expected to be prosecuted, they warned.
Kevin Austin, deputy director of agriculture, fisheries and the natural environment, said: "Our job is to protect fish stocks and improve fisheries.
"This includes rescuing fish in distress, improving habitat and restocking rivers with 450,000 fish a year.
"The majority of anglers, who fish legally, rightly demand that we take action to catch offenders.
"Our enforcement officers, supported by Angling Trust voluntary bailiffs, will be targeting illegal fishing.
"We urge anyone to report illegal fishing as quickly as possible by calling our incident hotline on 0800 80 70 60."
Last year the Environment Agency enforcement officers ran 670 close season patrols, reporting 122 anglers for illegally fishing in the close season.
You can check which still waters and canals still have a close season in operation by checking the byelaws which apply in your area at https://www.gov.uk/government/collections/local-fishing-byelaws.