Maps of the Old Bedford River and Delph

Here's a useful couple of schematics of the Old Bedford and the Delph, which shows how the system operates to allow excess water to collect on the Ouse Washes before it can be discharged out to sea via Welmore Sluice and the tidal Ouse.

This is one of the more vulnerable areas of the Fens, as far as the impacts of climate change and rising sea levels are concerned.

It's also likely to become one of the areas where pike fishing becomes more vulnerable in years to come, as conservation groups buy up areas of land to turn them into new wetland reserves, to replace threatened coastal habitats for wading birds.

For now, it remains one of the more challenging parts of the system, partly because of the impacts of siltation and periodic problems with brackish, turbid water being allowed into the lower reach of the Bedford to replenish levels for irrigation during dry summers, and occasional fish kills caused when the water "turns" after heavy rain, causing oxygen levels to crash.

Pike are mobile and seemingly in decline on both drains. A few big fish were caught last winter, from areas off the beaten track. But like many of the drains in this part of the Fens, those who were successful had to put a  lot of hours in and some long walks to find them.

They're still fascinating waters to fish, partly because both the Bedford and Delph were dug when the drainers first began to shape the Fens into the landscape we know 300 years later.

The map below gives a view of the Middle and South levels, bordered by Well Creek, the Ely Ouse and the Old West. It's perhaps no wonder where to start is the dilemma many pike anglers face as autumn nears.

Did maps show best pike fishing spots in the Fens?

I wonder what we did before Google Earth was invented. Pored over maps, I suppose. Or got lost.

Nowadays, we can explore waters to heart's content using Google Maps on our computers, and use navigation apps on our phones which show us how to get to some far-flung spot. One thing computers and iPhones can't yet do is show us where the fish are.

But the Environment Agency had an answer to that one a few years ago, when it went published  maps compiled after acoustic surveys of some of the rivers and drains in the Fens, using different colours to show the concentrations of fish found in different areas. Red meant lots of fish. Yellow meant not many.

Back in 2007, I wrote this at the time:

 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.

EA fisheries scientist Justin Mould said: "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."

Angling Times ran with the story, reproducing part of one of the maps. I'm sure I wasn't the only one who  got hold of them, fished a few of the red bits, caught sod all and went back to more traditional methods of fish location like getting off my ass and looking for them.

I wonder if anyone's still using the EA maps...