Pike anglers could soon be using Environment Agency survey maps to help them understand the mysteries of prey fish movements.
Finding the prey can often be the key to locating the predator, or so the oft-quoted theory goes.
And EA staff who like to wet a line in their spare time have been using the survey results to plan their own fishing, one of its fisheries scientists has revealed.
The revelation comes in the latest edition of Angle, the EA's magazine for anglers in its East Anglian region.
"Every angler wants to know where are the fish. Well, we have the maps that can tell you," it says.
The article explains how data collected from electronic surveys of rivers is plotted into maps. The piece is illustrated with a map of the Great Ouse between Ten Mile Bank and its confluence with the River Wissey, near Downham Market, in Norfolk.
A large concentration of fish is shown immediately downstream of the infall, which will be of no surprise to anyone in that part of the world.
At the time the survey was carried out last July, the swims shown as having the highest density of fish were producing 100lbs nets of bream and tench.
But EA fisheries scientist Justin Mould goes on: "I'm an angler myself and I can tell you they really do work. I've had some memorable fishing trips using these maps.
"I used the maps to identify where there might be shoals of prey fish and then went fishing for the predators that would be aound them."
Mould said his best catch using this technique was a 14lbs zander.
"Fish move, of course, so the maps are never 100 per cent accurate. But it does show you stretches where the fish are likely to be.
"These maps, once they are made, can be distributed to anglers free of charge. All they have to do is ask."