Patterns and determinants of helminth communities in the Acipenseridae (Actinopterygii: Chondrostei), with special reference to the lake sturgeon, Acipenser fulvescens

Patterns, processes, and some hypotheses regarding the structure of helminth communities in freshwater fishes have been investigated using sturgeons (Acipenseridae), a widely distributed group of basal actinopterygian fishes. Analyses at the infracommunity and component-community levels for one species, Acipenser fulvescens, indicated occasionally dense, but isolationist, gut helminth communities with moderate species richness and a high degree of predictability conferred by host-specific helminths that dominated the communities. Largely predictable helminth communities are also characteristic of acipenserids from Siberian and Ponto-Caspian drainages and basins. Although host specificity was the major determinant of helminth community diversity in most acipenserids, exceptions were found in sturgeons of the Aral Sea drainages, where non-host-specific parasites dominated the helminth communities. Gut complexity and evolutionary age were both found to be poor predictors of community richness in sturgeons an...