These documents by Natural England provide an account of the ecological requirements of the allis and twaite shad Alosa alosa and A. fallax, and a protocol for monitoring the species.
Ecology of the Allis and Twaite Shad (IN107)
Monitoring the Allis and Thwaite Shad (IN123)
This is part of our Good Practice Guidance for Fish, produced by Vaughan Lewis, Steve Coates and Kerry Sims.