Our placement student Alex visits a fish rescue at Tinsley, on the Sheffield & Tinsley Canal and describes the method used to rescue fish before we start work.
It was my first ever fish rescue on Tuesday so on a cold but amazingly sunny March morning we set off from Leeds to Sheffield to check on the progress of the lock stoppage at Tinsley on the Sheffield & Tinsley Canal. As the water has to be drained for a lock stoppage, the guys from MEM Fisheries were carrying out a fish rescue to remove fish from the lowered sections of the canal.
The way this works is, in the section between each pair of locks (a pound) more water is let through the bottom lock than the top lock so the water level lowers and this allows the fish rescuers to climb in with their small boat full of equipment, in their nice warm dry suits, so they can wade across the pound.
Watching a canal lower is always an exciting experience as it is very rare to see the walls and bottom of the channel as this can expose interesting wildlife such as mussels and you never know what could be at the bottom.
This is especially exciting if you happen to be the train spotter equivalent for shopping trolleys, as we found a pile of no less than 20 shopping trolleys from over the years below a bridge! While we can’t stop anti-social behaviour, opportunities like stoppages and fish rescues are great for clearing out the odd things that wind up in the canal, which recently included a WW1 medal at Tinsley!
The actual fish rescue consists of a process called electrofishing. While this may sound a bit maniacal from a fish’s perspective, it is actually a very efficient and safe way of relocating fish when we carryout a stoppage and have to drain a pound.
Electrofishing works by the rescuers wading through the lowered water with metal detector like equipment that passes a mild electric current through the water. This temporarily stuns the fish so that they float to the surface and are collected in nets and put in a large bucket that is then transported to a section of the canal where there is water.
I was excited to see that during this fish rescue a total of 230lbs of fish was removed, including roach, bream, pike, tench, perch, ruffe, gudgeon, dace and bullhead. It’s amazing all the different species that were found.
The Canal & River Trust has top team of committed experts and enthusiasts, who help to protect our waterway environment and improve it for both people and nature. Follow this blog to find out more about the hugely varied work they carry out.See more blogs from The environment team