Population dynamics and community analysis of the parasite fauna of juvenile spot, Leiostomus xanthurus (Lacepede), and Atlantic croaker, Micropogonias undulatus (Linnaeus), Sciaenidae) in two estuaries along the middle Atlantic coast of the United States

Abstract

The parasite communities of juvenile spot, Leiostomus xanthurus Lacepede, and Atlantic croaker, Micropogonias undulatus (Linnaeus), changed with size, season. and geographical area. A total of 21 parasitic species occurred in juvenile spot and 19 occurred in juvenile croaker from Chesapeake Bay and Pamlico Sound. More parasitic species were acquired as juveniles grew, diversified their diets, and consumed larger numbers of intermediate hosts. They were also exposed to infective larvae of parasites with direct lifecycles over long periods of time. Equibility and, thus, diversity were depressed because of large numbers of Diplomonorchis /eiostomi Hopkins, I941 that dominated the parasite communities of both species. Although spot and croaker from both estuaries shared eight and six parasites, respectively, many of these non‐specific parasites (generalists) were more common in both spot and croaker from one estuary than from the other. All species occurring in both hosts have indirect life cycles suggesting that the availability of certain intermediate hosts as prey was an important determinant of infection. Estuary of residence was clearly as important as host species identity in determining parasite community structure.