Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


Parasite communities of spot, Leiostomus xanthurus, and Atlantic croaker, Micropogonias undulatus, were examined to determine if (1) their structure changed with host age, (2) geographical location affected community structure, (3) food habits affected community structure, and (4) their parasite communities are predictable. Juvenile fish were collected monthly from Chesapeake Bay and Pamlico Sound. Adult fish were collected offshore north of Cape Hatteras in fall, and offshore south of Cape Hatteras in spring and fall. A total of 21 parasitic species occurred in juvenile spot and 19 in juvenile croaker from Chesapeake Bay and Pamlico Sound. The parasite communities of juvenile fishes varied with size, season, and area. Although juvenile spot and croaker shared eight and six parasites between estuaries, respectively, many nonspecific parasites (generalists) were more common in both spot and croaker from one estuary than the other. The estuary of residence was as important as host species identity in determining parasite community structure. Twenty-three species of metazoan parasites were recorded from adult spot and 26 from adult croaker. of the 33 parasitic species found, 17 occurred in both spot and croaker. All parasites had overdispersed or clumped distributions among hosts. Adult spot and croaker collected offshore had much greater species-richness, diversity, and total number of individual parasites than juvenile fishes collected in adjoining estuaries. The number of species and diversity of parasites in adult fish was greater in croaker than spot. However, when only gastrointestinal helminths were considered, spot had greater species-richness as well as greater numbers of individual helminths. Comparison of adult spot and croaker parasite faunas collected offshore indicated that their respective parasite component communities were distinct and that similar infracommunity variability existed in both hosts. Although the parasite dominance hierarchy in adults of both species varied slightly between areas and seasons, there appeared to be predictable dominant species. The core species were accompanied by subordinate, less predictable species. Variability in both relative intensities and presence absence of parasites within communities resulting from their diverse diets made them less predictable than those of other vertebrates with less diverse diets.



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