Weir Improvements Boost River Mole Salmon

Improvements on the Mole have opened up spawning habitat and boosted fish returns.

Populations of Atlantic salmon, sea trout and lampreys appear to be booming in Devon’s River Mole after two consecutive years of record breaking returns.

Over recent decades salmon populations have been in decline in many rivers across the south west but the River Mole appears to be bucking the trend, thanks to some major works carried out in 2010 on a weir at the base of the Mole, a tributary of the River Taw.

Head Weir was once a 3m high, smooth-faced concrete structure that spanned the river channel, preventing migratory species of fish, such as salmon and sea trout from reaching their spawning and nursery grounds further upstream.

Thanks to a project undertaken by the Westcountry Rivers Trust, the Environment Agency and the River Taw Fisheries Association, the old weir was removed two years ago and a new state-of-the-art natural pool and riffle system was installed, the first of its kind in Britain. It is designed to restore more natural flow and channel characteristics that allow fish migration while still ensuring that some of the flow is diverted to the historic Head Mill (the original reason for there being a weir on the site). The new construction has been named ‘Head Weir Falls’.

This hasn’t just been good news for Atlantic salmon and sea trout populations. Since completion of the work, there have also been several sightings of one of the most primitive species of fish alive today, the sea lamprey. Sea lampreys spend most of their life out at sea but, like salmon, migrate back to freshwater rivers to spawn. The Westcountry Rivers Trust will be continuing work to improve passage for fish throughout the River Taw system as part of the Taw River Improvement Project, a three year project funded by Riparian owners and the Catchment Restoration Fund (CRF).

The project to replace Head Weir was delivered by the Westcountry Rivers Trust in collaboration with riparian owners on the River Taw and the Environment Agency. The Westcountry Rivers Trust is an environmental charity established in 1994 to secure the preservation, protection, development and improvement of the rivers, streams, watercourses and water impoundments in the Westcountry and to advance the education of the public in the management of water.

The Taw River Improvement Project (TRIP) is being delivered by the Westcountry Rivers Trust, who made the successful bid to the Environment Agency for funding from the Catchment Restoration Fund (CRF).