Date of Original Version
In marine systems, empirical studies demonstrating effects of macroparasites on host population dynamics are relatively few. We tested the effects of a copepod macroparasite infecting the gills of a small coral reef fish, the bridled goby Coryphopterus glaucofraenum. Fish that were naturally infected and uninfected were tagged as individuals and tracked in the field for 5 mo. Parasitism was associated with an increase in gill ventilation rate, and a reduction in feeding. More importantly, parasitized fish showed significantly reduced growth (by 66%) and gonad mass (by 68%) compared to uninfected fish, and parasitism increased instantaneous mortality by a factor of 1.8. Since the prevalence of infection was higher in areas of high goby density, parasiteinduced mortality is a possible cause of host density dependence. These results imply a major effect of parasitism on host population dynamics and suggest that parasitism warrants closer attention by marine ecologists.
Finley, Rachel J. and Graham E. Forrester. ʺImpact of Ectroparasites on the Demography of a Small Reef Fish.ʺ Marine Ecology Progress Series. 248:305-309. March 2003.