Spatial distribution of gill parasites of Lepomis gibbosus (L.) and Ambloplites rupestris (Raf.)

Precise positions with regard to gill arches, sides of gill hemibranchs (anterior or posterior), and their sections (dorsal, medial, ventral) were recorded on 25 specimens monthly to determine spatial distribution of gill parasites of Lepomis gibbosus (L.) and Ambloplites rupestris (Raf.). Data were collected on three groups of parasites, Monogenea, Copepoda, and glochidia. The data, treated synecologically, were analysed for spatial distribution using a two-factor ANOVA and Duncan's multiple range test.A significant preference for anterior sides of hemibranchs was noted for Monogenea and glochidia of L. gibbosus (P < 0.001). A definite affinity for anterior medial and posterior medial sections of hemibranchs was noted for Monogenea and glochidia of L. gibbosus (P < 0.001), while Copepoda of the same host were found most often on either anterior or posterior sections of hemibranchs (P < 0.001).A well-defined preference for gill arches, in descending order, two, three, one, and four was noted for Monogenea and glochidia of L. gibbosus (P < 0.001), while no such preference was found for Copepoda of the same host (P < 0.001). The spatial distribution patterns exhibited by the three groups of parasites of Ambloplites rupestris followed generally the same patterns as those exhibited by the gill parasites of L. gibbosus, the only exception being the preference for anterior sides of hemibranchs exhibited by Copepoda (P < 0.001).