Alosa alosa

Habitat & Distribution

An anadromous species that is strongly migratory. It is found in inshore waters and enters the rivers in spring when water temperatures reach 10-12\'baC and penetrates far upstream to spawn, normally only once, on stony ground, returning soon after to the open sea. On the Tamar they die, the spent corpses can be seen below the spawning grounds. They occur all around the coast of Britain with the main concentration being in the Thames estuary, Bristol Channel and around south-west England. Allis Shad are known to spawn in the lower reaches of the River Tamar, downstream of Gunnislake Weir and in associated rivers. They can be quite common in the Falmouth Bay and Estuary area in springtime. This species is found along the Atlantic coast from the Mediterranean to Scandinavia.

Threats

This species has been in decline since the mid-nineteenth century, due to interruption of its spawning migration resulting from obstructions along the various river courses. Deterioration of water quality as a result of agricultural and industrial pollution has also played a part. Many specimens are accidentally caught in nets, set for other fish species, in the open sea.

Conservation

Listed under Appendix III of the Bern Convention; listed under Annex IIa and Va in the EC Habitats Directive; It is also protected under Schedule 5 of the Wildlife and Countryside Act (1981), S.9 (1) \endash 1991, S.9 (4) (a) \endash 1998, against killing, injuring or taking. It is also on the UK List of Priority Species with its own Species Action Plan (SAP) and is an OSPAR priority and NIMF candidate species.