Abundance and Diet of Predatory Fishes in Phragmites, Treated Phragmites, and Natural Spartina Marshes in Delaware Bay

Abundance and diet of larger predatory fishes in Phragmites marsh creeks were compared with those in natural Spartina alterniflora marshes and Phragmites marshes exposed to herbicides and burning (treated marshes). The most abundant fishes (n = 3,107) caught in gill nets from June to November 2001 and May to November 2002 were Morone americana (white perch; 82 %) and Ictalurus punctatus (channel catfish; 6 %). Annual abundance of species varied inconsistently across habitats. Morone americana caught in Phragmites marshes had lower percent piscivory and gut fullness than those caught in Spartina or treated marsh creeks, perhaps due to reduced fish prey availability. The diet in Phragmites marshes also showed comparatively higher occurrences and dry weights of the dominant marsh surface fish Fundulus heteroclitus (mummichog). With the few exceptions noted for M. americana, larger, piscivorous fishes appeard to function similarly in all three habitats, perhaps because their relatively large home ranges may cross habitat boundaries. More research, at broader spatial scales, is needed to link the effects of marsh restoration on piscivorous fish behavior and movement.