ABSTRACT
Extant batoid species are grouped into 20 families and six orders that contain at least 513 species (McEachran and Dunn 1998; McEachran and Fechhelm 1998). The Rajidae is the most speciose family, with at least 232 species. Most batoids are benthic, feeding on crustaceans, mollusks, polychaetes, and fishes (McEachran and Dunn 1998; Ebert and Bizzarro 2007; Mabragana and Giberto 2007). Batoids have adapted to a wide range of habitats, occurring in all the oceans, and they are commonly found in shallow estuarine, coastal, and shelf regions and in depths up to 3000 m (McEachran and Fechhelm 1998; McEachran and Aschliman 2004). Although most batoids are marine, the family Potamotrygonidae and some species in the family Pristidae occur in fresh water (McEachran and Fechhelm 1998). Interest in batoid fishes has grown and is exemplified by developing fisheries (NEFSC 1999), population collapses (Brander 1981; McPhie and Campana 2009), and interactions
CONTENTS
6.1 Introduction ........................................................................................................................283 6.2 Demographics ....................................................................................................................284
