Work carried out at Denver Sluice by the Environment Agency has improved conditions for fish fry allowing more to survive during spawning.
This month King’s Lynn Angling Association, which controls the fishing in the Great Ouse Relief Channel in Norfolk, reported sightings of large numbers of fish around the sluice.
Environment Agency fisheries officers were optimistic of an improvement in the fishery as early as August when large numbers of small fish were recorded during a hydro acoustics survey.
A subsequent netting survey produced an amazing haul of fish including large perch and zander. These fish had been feeding on the huge shoals of roach and bream fry. The ‘catch’ also included three sea trout running upstream to spawn.
The highest densities of fish were seen at Downham Market, Magdalene and Saddlebow Bridges
Anglers used to travel far and wide to fish in the channel but the fishery declined in the 1980’s due to an increase in flow, reducing the chances of survival for the fry.
Environment Agency ecological appraisal officer Paul Wilkanowski said: ‘In the past many of the fry would have been flushed  into the tidal estuary and perished.  Now that the flow has changed thanks to the work at Denver, there is an abundant supply of fry.’
Work at the complex was carried out to maintain the tidal defences and so that more water could flow down the river in line with the Agency’s tidal river strategy, taking it away from the by-pass channel where the fish spawn.
This was achieved by carrying out repair work on the Little Eye sluices and installing an experimental compressed air desilting system.
The work at Denver sluice, cost about £1m.