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Allis shad Alosa alosa - Endangered

One of only two species of herring to be found in freshwater within the UK, this species occurs mainly in shallow coastal waters and estuaries: during the spawning migration adult fish penetrate well upstream. Though once widespread around the UK, Allis Shad populations have declined significantly in recent decades and the River Tamar is now the only known spawning site. The River is currently considered to be in unfavourable condition for the fish and for European Smelt, another Devon Special Species, largely due to the barrier to migration presented by Gunnislake Weir. In 2019 Natural England (NE) funded the Environment Agency (EA) to map Allis Shad spawning habitat upstream of Gunnislake Weir and investigate spawning distribution above and below the weir: this work has been completed and reporting is in progress. NE and EA have met with South West Water (SWW) who own the weir, and a consultant (Fishtek) has produced an initial plan of where the new fish pass that’s needed would go and what it would look like, once funding has been secured. Other potential threats include overfishing and pollution.

Map to show the Devon distribution of this species


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European smelt Osmerus eperlanus - Endangered

Declining throughout its range, this fish lives in estuaries and around the mouths of rivers, migrating upriver into freshwater during the spawning season before returning to the sea. Devon has one population, in the Tamar Estuary. The Tamar estuary is, through its designation in 2013 as a Marine Conservation Zone (MCZ), recognised as a nationally important spawning site: it is the only UK MCZ site where Smelt is protected. In 2018, the Environment Agency (EA) and Natural England (NE) mapped Smelt spawning habitat in the tidal freshwater reaches of the upper Tamar Estuary and investigated the spawning distribution of the fish. As for the Allis Shad, another Devon Special Species, the Tamar is considered to be in unfavourable condition for Smelt, largely due to the barrier to migration presented by Gunnislake Weir. A study is due to start early in 2020 on Smelt movements around the weir, by tracking them during and post-spawning to see if they can access the river upstream of the weir, and also to find out if Smelt return to the lower estuary or migrate to coastal waters. NE and EA have met with South West Water (SWW) who own the weir, and a consultant (Fishtek) has produced an initial plan of where the new fish pass that’s needed would go, and what it would look like, once funding has been secured. Other potential threats include overfishing and water pollution.