Pipeline will help scientists study fish migration

A £400,000 pipeline between the Cut-Off Channel and the Wissey will help eels and sea trout move to and from their spawning grounds - and help scientists learn more about how these rare species and commoner varieties of coarse fish migrate around the Fens.

As well as connecting the two waterways, the hi-tech siphon is rigged with sensors which can tell when a fish which has been implanted with a special tag passes through it. As well as tracking devices, the pipeline also has infra-red cameras, allowing Environment Agency fishery officers to keep a watch on which species are using it.

The EA-funded project, paid for by efficiency savings within the agency, is the first of its kind in the country. Similar schemes are planned elsewhere, as the agency steps up its work to conserve rare species and monitor the health of our rivers.

"It's an all-species, all-singing and dancing fish pass," said Kye Jerrom, a fisheries technical specialist with the EA. "It's a massive project. It's such a significant site it needed something like this."

The pipeline (right...) was designed and built in Holland, before being shipped across to Stoke Ferry in sections. It has a series of baffles and pools inside, to ensure the flow remains negotiable for all species. It also has a special eel lane, which helps anguilla ascend on its way inland, where it spends its life before returning to the sea for the long journey to its far-flung spawning grounds. 

It also contains sensors which can detect PIT (Passive Integrated Transponder) tags. Around 150 fish have been caught and tagged as part of a special research project. The EA plans to tag a further 200 each year, to build up an ongoing picture of fish movements. So far roach, rudd, chub, tench, trout and eels have been tagged at Stoke.

Scientist Karen Twine, from the International Fisheries Institute at Hull University, is known as the Barbel Lady for her work radio-tracking barbel on the Great Ouse. The study showed that barbel in the river were not being predated by otters, but were declining because their spawning grounds were silting up.

Now she's shifted the focus of her research to the Fens, where she'll be keeping an eye on Eel 2, Trout 3, Roach 19 and other tagged fish, to monitor their movements as they travel from one part of the system to the other.

As well as the PIT tags, Karen said she'll be using acoustic tracking - along similar lines to her acclaimed barbel research - to learn more about what's going on in our rivers and drains. You can just about see the tiny tag in the picture.

While there are no plans to study pike at present, the PIT tags might just do so by default. For the gizmos should keep on working if Roach 19 happens to get eaten by one.

This is exciting, cutting edge stuff. Meet Kye and Karen and you can't fail to be impressed by their passion for their subject matter and their drive to advance our knowledge of how fish in our rivers and drains are faring.

There are hopes that similar siphons will be installed elsewhere - the next location which has been pencilled in is between the Ouse and the Relief Channel, at Denver. Maybe, just maybe, the future of our fisheries isn't quite as bleak as it's sometimes painted.

One thing's certain - we're going to find out a whole lot more about our bread and butter coarse fish, as well as rarities like eels and sea trout, over the next few years.