The ecology and conservation of Allis and Twaite Shad

Allis Shad Alosa alosa and Twaite Shad A. fallax are anadromous relatives of the herrings, spending part of their lives in the sea and returning to spawn in the rivers of their birth. Several 'landlocked' European populations also exist which live exclusively in fresh water. A non-migratory subspecies of Twaite Shad known as the Goureen or Killarney Shad A. fallax