Fairburn has been alive with the arrival of spring over the last couple of weeks which means we have amped up our work surveying the local wildlife. A couple of weeks ago were welcomed two of the RSPB’s ecologists to survey the fish population on the Coal Tips using a technique called Electrofishing
Electrofishing is commonly used by scientists to sample fish population in bodies of freshwater. As well as sampling fish population’s electrofishing can also be used to catch and tag fish species for other studies.
So how does it work?
A field of electricity is passed through the water using a pair of electrodes that are placed in the water. These electrodes send a current through the water that cause a muscle response in the fish. This pushes the fish towards the net so they can be caught, measured and weighed. After these measurements are taken the fish are released and free to swim away. The process causes no harm to the fish and they resume normal function just a couple of minutes after being caught.
The reason we monitor the fish populations in our lakes at Fairburn is they are a vital food source for some of our spectacular species who inhabit the site. One of these magnificent bird species is the Bittern.
Between 1970 and 1990 there was significant decline in bittern numbers with the root cause of the sustained decline being the loss and ruin of reed beds. Now in the UK we have a small and fluctuating population size that needs our help.
By monitoring and improving the reedbed habitat we have across RSPB reserves like Fairburn we hope to help the Bittern and increase their population size. Electrofishing is one of the ways to monitor their habitat and food source.
The team managed to catch a small number of fish, these were likely to be the offspring of fish we stocked in 2013 and represent a larger population that managed to avoid the team. This population helps support the bitterns who make their home on the reserve and shows our management is helping make a difference.