Nest-building jawless fish caught on camera

Rare footage of Brook Lampreys – an eel-like jawless fish – has been caught on camera by an Environment Agency fisheries staff during a visit to Berkshire’s Whitewater River near Reading.

The secretive fish can be seen busily building nests in preparation for the spawning season. The video is a rare glimpse of how these creatures live under the tranquil waters of the county’s rivers.

Fisheries Officer Dominic Martyn, who shot the footage, said: “During the survey we came across spawning Brook Lamprey and I used my colleague’s underwater camera to record the event taking place. It was amazing to see and I am so pleased we have this footage as it highlights how incredible this ancient species is.”

The film reveals how the females laboriously construct nesting hollows in the gravel bed of the stream, moving one tiny piece of gravel a time in their suckers to make a depression in the bed. It sometimes takes several of these small animals to shift a larger stone. They shed their eggs into the water and the fertilised eggs stick to the stones.

During their life-cycle, young lampreys live buried in the silty beds of the river margins, where the water is still. They are blind, and feed on minute particles in the water. After several years of laval growth, they metamorphose into adults and migrate away from the nursery areas. Brook Lamprey remain in the river but do not feed. Once they spawn they die and the process starts all over again with their offspring.

Lampreys are listed under international conservation legislation and the Environment Agency has a duty to conserve these unique creatures to ensure their survival within our natural habitats. There are three different species of lampreys in Britain, the Brook Lamprey, the River Lamprey and the Sea Lamprey.  However, over the past centuries, the habitats they depend on have suffered from a range of impacts such as pollution, changes in land-use and river engineering.

Dominic added: “Pollution can have a very direct toxic effect, and silt from surrounding land can smother important breeding grounds. River engineering can remove entire nursery areas. Weirs and dams can also block their migration to feeding or breeding habitats.

“We urge anglers to be aware of Lampreys as they can sometimes be caught when fishing for coarse fish and salmon.  If you do catch one, please return it as soon as possible and with the minimum of handling.”