Structuring mechanisms of yellow perch (Perca flavescens) parasite communities: host age, diet, and local factors

Abstract

Seventeen parasite species were recovered from perch in four small Canadian Shield lakes with different fish species compositions. Parasite species such as Urocleidus adspectus Mullier, 1936, Bunodera sacculata Van Cleave and Muller, 1932, and Proteocephalus pearsei La Rue, 1919 are phylogenetically associated with perch and (or) percids; others, such as Crepidostomum cooperi Hopkins, 1931, Spinitectus gracilis Ward and Magath, 1917, and Echinorhynchus salmonis Muller, 1784, are related to dietary sharing; and larval species such as Apophallus brevis Ransom, 1920 and Raphidascaris acus (Bloch, 1779) are phylogenetically tied to perch but also to bird and fish definitive hosts. Variable patterns of dominance were dependent on trophic level and other host species in the system. As matrix fill increased with host age, the dependence of the parasite component communities on the given infracommunities decreased, confirming that predictable component communities depend on repetitive infracommunities. Shifts in dietary preference with age and (or) size and dietary sharing among host species were important in producing repetitive infracommunities. Host diet and age contributed significantly to the rate of parasite species accumulation. Parasite composition at the infracommunity scale changes with local community structure across the watershed and regardless of lake connectivity. The presence of ecologically derived parasite species is strongly influenced by local factors.