Comparative assessment of distribution and abundance of Sphaerostomum bramae and S-globiporum (Trematoda, Opecoelidae) in populations of definite hosts [Russian]

摘要

The distribution and abundance of the trematode Sphaerostomum bramae Miller 1776 in populations of bream, white and blue breams and S. globiporum Rudolphi 1802 in populations of ide and roach from the Rybinsk Reservoir were studied. The relative abundance of the trematodes was calculated for hypothetical fish populations. The bream was found to be the main host for S. bramae among the three host species investigated. All age groups of bream were infected except for fingerlings. Infection of the fishes increases with age. Bream is a host for about 90.8% of trematodes. 35% of them fall on immature fish of ages 3+ - 4+. The ide is the main host for S. globiporum (85.5% of all trematodes). All size fish classes we infected: their abundance was evenly disttibuted, and the majority of trematodes was found in fishes of age 12+-13+. In he roach, only mature individuals were infected. The reasons, to which one or another fish species becomes the major host for parasites are discussed.