Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams
Article first published online: 2 APR 2013
© 2013 John Wiley & Sons Ltd
Volume 58, Issue 7, pages 1392–1404, July 2013
How to Cite
Ciparis, S., Iwanowicz, D. D. and Voshell, J. R. (2013), Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams. Freshwater Biology, 58: 1392–1404. doi: 10.1111/fwb.12135
- Issue published online: 5 JUN 2013
- Article first published online: 2 APR 2013
- Manuscript Accepted: 26 FEB 2013
- Virginia Department of Game and Inland Fisheries
- Virginia Environmental Endowment
- Federal Aid in Sport Fish Restoration
Nutrient enrichment is a widespread environmental problem in freshwater ecosystems. Eutrophic conditions caused by nutrient enrichment may result in a higher prevalence of infection by trematode parasites in host populations, due to greater resource availability for the molluscan first intermediate hosts.
This study examined relationships among land use, environmental variables indicating eutrophication, population density of the pleurocerid snail, Leptoxis carinata, and trematode infections. Fifteen study sites were located in streams within the Shenandoah River catchment (Virginia, U.S.A.), where widespread nutrient enrichment has occurred.
Snail population density had a weak positive relationship with stream water nutrient concentration. Snail population density also increased as human activities within stream catchments increased, but density did not continue to increase in catchments where anthropogenic disturbance was greatest.
Cercariae from five families of trematodes were identified in L. carinata, and infection rate was generally low (<10%). Neither total infection rate nor the infection rate of individual trematode types showed a positive relationship with snail population density, nutrients or land use.
There were statistically significant but weak relationships between the prevalence of infection by two trematode families and physical and biological variables. The prevalence of Notocotylidae was positively related to water depth, which may be related to habitat use by definitive hosts. Prevalence of Opecoelidae had a negative relationship with orthophosphate concentration and a polynomial relationship with chlorophyll a concentration. Transmission of Opecoelid trematodes between hosts may be inhibited by eutrophic conditions.
Leptoxis carinata appears to be a useful species for monitoring the biological effects of eutrophication and investigating trematode transmission dynamics in lotic systems.