Official figures from the Environment Agency show just 297 salmon and sea trout were recorded going through the fish pass at the Tees Barrage last year – the lowest number since counting began in 2011. However, as Lee Butler, from the Canal and River Trust, told Stuart Laundy, this does not tell the whole story.
ON the face of it, these are tough times for migratory fish in the Tees. From a high of 1,661 in 2012, just 297 were recorded passing through the Tees Barrage, at Stockton, last year.
The river has now been classed as “at risk” and from this season any salmon caught on the Tees must be released.
In fact, it’s catch and release only for the next five years.
But is the situation as bad as it seems?
Not according to Lee Butler, team leader with the Canal and River Trust.
The trust is responsible for managing the barrage along with a 22km stretch of the river to its former tidal limit at Low Worsall.
“Before the barrage was constructed, salmon and sea trout had no problem getting past – but the river was that dirty, there were not so many fish,” says Mr Butler.
It’s now 23 years since the barrage – built at a cost of £55million as part of a wider regeneration scheme designed to breathe new life into Stockton – was officially opened by the Duke of Edinburgh.
“We are trying our hardest to get as many salmon and sea trout past the barrage as we can,” adds Mr Butler.
And it is a change in operations at the barrage that he says accounts for the declining numbers of fish counted by the Environment Agency.
“There is one fish pass used by the Environment Agency. In recent years we have changed operations and in the right conditions, virtually the full barrage is used as a fish pass.”
As a result, between four and seven times more fish jump the barrage gates than use the fish pass.
Mr Butler also points out that the narrow fish pass is only monitored for a certain number of days and never at night.
“We don’t know if we get more fish through on a night or not. More days will be monitored this year. Hopefully we will get a better picture.”
Salmon and sea trout can also head upstream via the international white water course, directly adjacent to the barrage, which includes a dedicated pass as well as the short and long courses.
And one of the most innovative ways of helping fish up the river was dreamt up by a member of the trust’s team based at Stockton.
A remote controlled device fitted to the top of the lock on the navigation channel, which allows shipping to pass through the barrage, was designed to fix open the lock gates with a gap of just 20cms.
This allows fish to enter the channel, but keeps seals out. It is then simply a case of closing the lock behind the fish and opening the top gates to allow them through – exactly the same as if a narrowboat was passing through a lock on a canal.
“That piece of kit cost only £176 and works really well,” says Mr Butler.
The trust is hopeful of landing a grant which will allow a metal frame to be installed across the navigation channel with 20cm gaps between bars to allow even more fish through.
As well as the physical barriers fish must overcome at the barrage, there is also the ever-present problem of seals, who are always on the look-out for an easy meal.
Anyone who has ever fished off the Gare at Redcar, where the Tees enters the North Sea, will attest to how efficient seals are at grabbing a snack.
“They are really intelligent. People have seen them going over the baks and getting upstream,” says Mr Butler.
“We have between 30 and 40 volunteer seal watchers and they do surveys, trying to find out how many we get and whether they are the same seals.
“We seem to get five at the most at any one time – three grey and two harbour seals – and it seems to be the same seals that come back all the time. The three big greys have made the barrage their domain.”
It is, says Mr Butler, an ongoing battle to find a system that is safe for the seals but is also a deterrent to keep them away from the migrating fish.
“We did use an acoustic device to deter the seals. It had no effect on the first seal, but it was an old one with a scar on its face and was probably deaf. The next two that came shot off. We are going to try the acoustic deterrent again this year.”
He says all these efforts have one common goal.
“We are trying every way possible to get fish past the barrage.”
