Environment Agency staff across the region have been staging a crackdown on illegal fishing.
To mark the start of the new season they organised a river blitz to check if people had the correct licences to fish.
They focused on rivers in Cambridgeshire, Northamptonshire, Lincolnshire and Norfolk.
They were also joined by the police during the patrols in Cambridgeshire and Northamptonshire.
The officers checked 285 people for licences and found that 268 (94 per cent) had renewed in time for the new season.
The 17 who did not have the £27 annual licence were given Offence Report Forms.