There are early indications that populations of Atlantic salmon and sea trout are booming in the River Mole in Devon, after two consecutive years of record breaking catch statistics. 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 this 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. Two years ago we undertook a project, along with the EA and the River Taw Fisheries Association, to remove the old weir and replace it with a new state-of-the-art natural pool and riffle system, the first of its kind here 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 rare 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).

You can see some footage of the rare sea lamprey on the News and Media page of our website.