The Allis Shad and Twaite Shad occur along the Atlantic coast of Europe, South to the Iberian Peninsula Including the Mediterranian Sea.
The Allis Shad is a migratory species living in shallow coastal waters except during the breeding season when it travels into rivers in order to spawn.
The Twaite Shad also migrate between fresh and saltwater. Both species have experience great decline over much of Europe and are virtually absent from many rivers in the England where once they were common.
Both of these fish can be distinguished from the other European species by the presence of a large blackish blotch behind the gill-opening. Both species look quite similiar and can most readily be distinguished from each other by the gill rakers. The Allis Shad has anywhere from sixty to eighty very fine and long gill-rakers along the concave edge of the first branchial arch, where as the Twaite Shad has twenty-one to twenty-seven stout, stiff gill-rakers.