Freshwater Shad Monitoring Data

Citation

Description

The Rivers Wye, Usk and Tywi are designated as a Special Area of Conservation (SAC) under the EC 92/43/EEC Habitats Directive for several features including twaite shad (Alosa fallax) and allis shad (Alosa alosa). Shads are migratory members of the Clupeidae (herring family) that ascend rivers to spawn in late spring. The populations of both species are threatened in Europe mainly due to obstructions to migration and issues surrounding water quality. In the UK, significant populations of shad spawn in the Rivers Severn, Usk, Wye and Tywi. The River Wye, Usk and Tywi have been designated as a Special Area of Conservation (SAC) for shads and other features including salmon, lampreys and bullhead. However, it is not certain whether a breeding population of allis shad still exists. The former Countryside Council for Wales (CCW), and now Natural Resources Wales (NRW) is responsible for monitoring the condition of shad populations within SACs and to ensure the maintenance of favourable conservation status within these designated sites. This dataset comprises of a number of surveys entered into Recorder 6 which have been packaged for dissemination onto the NBN Gateway. Detailed information about each of the survey data can be found under their individual metadata entries.

Purpose

Environment Agency Wales (EAW) and Countryside Council for Wales (CCW), recorded shad egg survey data are available for the River Wye Usk and Tywi. A kick sampling methodology was undertaken at each site with the number of eggs found in each kick recorded.

Sampling Description

Taxonomic Coverages

Geographic Coverages

Bibliographic Citations