RANDY C. LANDRY AND WILLIAM E. KELSO, School of Forestry, Wildlife, and Fisheries, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA

Parasitism is common in wild fish populations, and the species and numbers of parasites that infect fishes are influenced by many factors, including physicochemistry of aquatic habitats. The objective of this study was to assess differences in parasite assemblages of young-of-the-year largemouth bass among lacustrine, riverine, and swamp habitats in the lower Atchafalaya River Basin. We collected 244 largemouth bass ranging from 37 to 123 mm TL and identified 14 parasite taxa from those fish. Kruskal-Wallis tests were used to assess differences in median (m) parasite loads among size and habitat groups. Fish (> 80 mm TL) collected from lacustrine habitats had total-parasite loads (m=139) that were significantly higher than total-parasite loads of fish collected from riverine habitats (m=76.5; P<0.05). Posthodiplostomum minimum loads (m=33) of fish (>80 mm) collected from lacustrine habitats were significantly higher than in riverine (m=5.5; P<0.05) or swamp (m=4; P<0.05) habitats. Tapeworm plerocercoid prevalence was higher in riverine habitats (65 and 50%) than in swamp (37 and 8%) and lacustrine (13 and 10%) habitats. These data suggest that physicochemical characteristics of Basin habitats may significantly influence parasite assemblages of young-of-the-year largemouth bass.