MEPS 248:305-309 (2003)  -  doi:10.3354/meps248305

ABSTRACT: 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, parasite-induced 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.

KEY WORDS: Pharodes tortugensis · Coryphopterus glaucofraenum · Host-parasite interaction · Parasitic gill copepod