PATTERNS AND DETERMINANTS OF HELMINTH COMMUNITIES IN THE ACIPENSERIDAE (ACTINOPTERYGII, CHONDROSTEI), WITH SPECIAL REFERENCE TO THE LAKE STURGEON, ACIPENSER-FULVESCENS
A. Choudhury et Ta. Dick, PATTERNS AND DETERMINANTS OF HELMINTH COMMUNITIES IN THE ACIPENSERIDAE (ACTINOPTERYGII, CHONDROSTEI), WITH SPECIAL REFERENCE TO THE LAKE STURGEON, ACIPENSER-FULVESCENS, Canadian journal of zoology, 76(2), 1998, pp. 330-349
Patterns. processes, and some hypotheses regarding the structure of he
lminth communities in freshwater fishes have been investigated using s
turgeons (Acipenseridae), a widely distributed group of basal actinopt
erygian fishes. Analyses at the infracommunity and component-community
levels for one species, Acipenser-fulvescens, indicated occasionally
dense, but isolationist, gut helminth communities with moderate specie
s richness and a high degree of predictability conferred by host-speci
fic helminths that dominated the communities. Largely predictable helm
inth 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 acipens
erids, exceptions were found in sturgeons of the Aral Sea drainages, w
here non-host-specific parasites dominated the helminth communities. G
ut complexity and evolutionary age were both found to be poor predicto
rs of community richness in sturgeons and other basal actinopterygians
. The stochastic component of the gut helminth fauna is determined by
shared trophic category and sympatry with other major benthivorous fis
hes, mainly benthic coregonines in Holarctic drainages and benthic ost
ariophysans (e.g., cypriniforms) elsewhere. Although some predictions
of ''evolutionarily mature'' communities are partially fulfilled, the
authors of this study caution that owing to differences in the biology
and history of individual species and groups and the diversity of fis
hes in general, broad generalizations about the factors shaping fish p
arasite communities will be difficult to make.