Stock boost for Great Ouse barbel
A hundred thousand month-old barbel fry have been stocked into the Great Ouse above Bedford and its tributary the River Ivel in a bid to replenish stocks.
The work is in response to feedback from anglers that there are fewer barbel in the Ouse than in its heyday in the 1980s and 90s.
Nobody is sure if the decline is down to habitat loss, natural causes, predation or a combination of the three, but thanks to the latest stockings the future of barbel on both rivers seems assured.
The Environment Agency is responsible for improving the fisheries, with all the work it does funded solely from rod licence revenue. Fisheries technical specialist Kye Jerrom, from the EA’s Brampton depot, manages projects carried out in the Cambridgeshire and Bedfordshire river catchments.
He said: “We’ve been carrying out habitat improvements and research into barbel for 12 years now, and this stocking is just a small snippet of the work we’re undertaking.
“Our aim is to ensure the Upper Ouse is a sustainable fishery, and a natural one. This means it shouldn’t be reliant on top-ups of fish. Most of our efforts are being invested into ensuring that the habitat of the Ouse and its smaller tributaries, like the Ivel, is suitable for barbel.
“That means retaining stocks, providing cover for juvenile fish and ensuring successful spawnings – that’s how you make a real difference.”
“We stock fish to provide a helping hand – a boost to natural populations. It’s a useful fisheries management tool, but by no means the only one.
Kye continued: “We’ve learnt an awful lot from our research. Our studies indicate the primary cause of the barbel decline is a poor fry survival rate and reduced spawning success.
“Although there are a number of factors affecting natural recruitment, two of the most problematic which have been outlined in our studies are the lack of clean spawning beds due to sediment build-up, and predation on barbel eggs by the invasive signal crayfish.
“This is why we have chosen to stock the fry and bypass the problems brood fish are currently experiencing in the wild.”
A question many anglers are asking is, why stock thousands of small fry as opposed to fewer, but larger, barbel? Kye explained the EA’s stance.
“Larger fish may well have better survival rates than the estimated one per cent from our latest stockings, but those fish are unlikely to be as fit and as successful as adults that have survived from very young fry.
“These will be a lot more ‘streetwise’, so to speak, when they mature, having spent virtually their whole life in the river. This will hopefully make for a hardier fish long-term.
“It also doesn’t feel right stocking larger fish – yearling fish seem much more natural.”
All the EA’s stocking efforts would be pointless unless they proved to be sustainable for
years to come, and this is why Kye and his team have also carried out a succession of habitat improvements, including creating areas suited to juvenile barbel.
He explained: “We’ve constructed several refuge areas for fry and juvenile fish, the latest of which is in Harrold Country Park, one of the six stocking locations. These areas offer an escape from floodwater and are very important for fry survival – only a day after opening this particular relief channel it was full of fry!
“We’ve also restored several areas, including Adams Mill, which produced the record. Here we’ve installed structures to halt bank erosion, which in turn keep the stretch narrower and faster, helping to keep the spawning beds clean.
“Alongside this, we’ve added several flow deflectors, which again help stop sediment build-up on the gravels and raise oxygen levels.
“We can’t do all this work ourselves,” Kye continued.
“The fisheries team also works with local anglers, angling clubs and landowners, as they are the key to improving the fishery catchment scale. All this work is reliant on rod licence income, 100 per cent of which will be ploughed back into projects such as this.”