What is Electrofishing?
Electrofishing is a method for surveying fish stocks in rivers. Electrofishing involves the use of a backpack-mounted electro-pack with a hand held electrode that passes an electric current through the water in a river. This temporarily stuns the fish within it and causes them to float to the surface where they are collected with a net. Details such as species and size are recorded prior to release. Fish can then be measured and recorded and either returned to the water or removed and translocated to other areas.
Why would Electrofishing be required?
Electrofishing is usually required to evaluate the status of a water body and survey its fish stocks. An electrofishing survey can be used to establish the fish species that are present in a particular river channel. The condition of the fish and level of maturity can be a useful indicator of the
quality of the waterway and its importance to fish life.
Electrofishing is also required to remove fish from a section of river channel prior to the undertaking of in-stream works. Where the in-stream works have the potential to harm or possibly kill fish, the fish are removed for their own welfare, and relocated to another point upstream in the river channel. Such in-stream works might involve drying and over-pumping a section of a river's channel in order to install pipework or construct foundations for bridges or other installations. Fish would not be able to survive the drainage of a river's section, and so are removed in advance of the works commencing.
How is Electrofishing carried out?
Nets are installed across the width of a river channel at locations upstream and downstream of the section of river channel in which the electrofishing is to take place? The electrofishing equipment is then used by our trained professional staff in the section of river channel between the nets. Other staff members collect fish with nets as they appear and are drawn towards the electrode net. All fish are captured are transferred by net to temporary holding tanks or are relocated immediately upstream.