LIFE - Shad Severn: Conservation and restoration of twaite shad in the Severn Estuary Special Area of Conservation

PROJECT DESCRIPTION

BACKGROUND

Prior to the mid-19th Century, twaite shad (Alosa fallax) was an economically important species in the Severn river basin. Within three years of the installation of navigation weirs fishing ceased. In the UKs third report on the Habitats Directive, the UK Atlantic bioregion conservation status for Twaite shad is identified under Article 17 as unfavourable inadequate improving (due to recent fish passage improvements on other Natura 2000 network sites). The overall assessment is inadequate because of the impact on range and population of barriers to migration.

The Severn estuary and Bristol Channel are an important habitat for juvenile and adult twaite shad.

Open migration between the adult and juvenile habitats in the estuaries and spawning freshwater rivers is critical. At maturity, twaite shad stop feeding and gather in the estuaries of suitable rivers in late spring, moving upstream to spawn from mid-May to mid-July. Spawning takes place in water flowing over stones and gravel, among which the eggs sink. The young fish move downstream in the current to the quieter waters of the upper estuary where they start to feed and grow. Currently, the species is unable to migrate further upriver than Worcester on both rivers Severn and Teme, reducing its spawning range to approximately 20 km rather than the 273 km total historic range. The suitability of habitat upriver means that removal of barriers at Worcester would significantly increase the range of the species.

OBJECTIVES

The Unlocking the Severn for LIFE project will improve access up and down the two key rivers for this species associated with the Severn Estuary Special Area of Conservation (SAC), directly impacting 57% of the UKs potential breeding stock and increasing access to favourable spawning and juvenile habitat by 195%, through the removal of seven barriers to migration upstream of the Severn Estuary Natura 2000 network site.

The objective of this project is to undertake work on two major rivers to secure a development towards favourable conservation status of the population of twaite shad in the Severn Estuary SAC by significantly improving access for the population of twaite shad to quality spawning and nursery habitat and re-establishing access to 253 km of the former natural range of the species in the rivers Severn and Teme will be a step towards favourable conservation status.

The project will benefit the UKs spawning population and the overall conservation status of the Natura 2000 network as the long term population expansion will benefit other catchments, including the Usk, Wye, Afon Tywi, Carmarthen Bay and estuaries and the Pembrokeshire Marine SAC. Barriers to migration mean the status of the twaite shad is unfavourable bad and deteriorating in other EU bioregions, so there are good opportunities for transfer of project outcomes to these regions.

Expected results: The project expects to achieve the following results:

By 2020, fish access isprovided for twaite shade across five artificial structures on the river Severn opening 190 km of historic spawning and nursery habitat associated with the Severn Estuary SAC;

By 2019, fish access is provided for twaite shad at two artificial structures on the River Teme, opening 63 km of historic spawning habitat associated with the Severn Estuary SAC;

By 2021, the twaite shad is present, and suitably protected, above Lincomb Weir on the Severn and Knightsford Weir on the Teme. Thenumber of individuals in the mid-reaches of the Severn and lower Teme increase from nil in 2015 to 50 in 2021 (and 200 by 2025), and the number of twaite shad spawning locations on the mid-Severn and lower Teme increase from nil to 5 by 2021 (and 20 by 2025);

By 2021, local communities understand the biological value and potential social and economic value of twaite shad, the river and the Natura 2000 network site through a series of events and dissemination actions that engage more than 8 million people;

By 2017, long-term monitoring is established to effectively assess twaite shad populations and connectivity in the Severn and Teme; and

By 2021, effective transnational exchange of best practice is established on twaite shad populations across its range in Europe. Project actions lead to the transfer of replicable actions to instigate similar projects across the Atlantic, Mediterranean, Continental and Boreal bioregions.