"This volume presents a synthesis of basic biological and conservation data for more than 30 species of sturgeons ..., paddlefishes ... and their fossil allies in the order Acipenseriformes. Since the Jurassic, the four families of sturgeon-like fish have been restricted to the Holarctic, where until very recently they flourished in most major river systems. Today, however, virtually all species of sturgeons and paddlefishes face difficult conservation issues." (Quoted from site)