dactylogyrids on the gills of roach in central finland: features of infection and species composition.monogenean parasites were examined from the gills of 660 roach (rutilus rutilus) in four interconnected lakes in central finland between february and november 1986 and in three of the same lakes between february and december 1988. one of the lakes is eutrophic and polluted due to a paper and pulp mill, one is oligotrophic and in a natural state, and the other two lakes are eutrophic. the prevalence of dactylogyrus infection was always high. differences between the lakes and the years were observ ...19911743852
development of monogenean communities on the gills of roach fry (rutilus rutilus).the formation and development of monogenean communities on the gills of roach fry was followed in 1992 from early june to october (size range 9 to 47 mm). roach fry (n = 291) were sampled weekly from the small, humic river rutajoki in central finland. a further 209 roach fry were reared in a fish farm supplied by water from the river. four dactylogyrus species were found: d. nanus, d. crucifer, d. micracanthus and d. suecicus. other species found on the gills were gyrodactylus sp. and paradiploz ...199910363281
parasite communities as indicators of recovery from pollution: parasites of roach (rutilus rutilus) and perch (perca fuviatilis) in central finland.we compared parasite communities in fish taken from a polluted lake (l. vatia) and two control lakes before (1986) and after (1995) nine years of markedly reduced chemical and nutrient loading from a pulpmill in central finland. discriminant analyses of the 1995 data, using a function based on the 1986 data, showed that the parasite communities in the fish from the two control lakes had changed relatively little, whereas those from l. vatia had converged on those from the mesotrophic control lak ...200314667171
the predictability of helminth community structure in space: a comparison of fish populations from adjacent lakes.patterns in helminth community structure can suggest that various processes are acting to shape parasite communities into organised, non-random assemblages of species. it is not clear, however, whether a pattern observed in one host population at one time would be observed again at another time, or at the same time in a different but comparable host population. here, we test the repeatability of parasite community structure in space, and to a lesser extent time, with data on helminth parasites o ...200212204223
occurrence and histological response of raphidascaris acus (nematoda: ascaridoidea) in roach from four lakes differing in water quality.seasonality and size-related infection of raphidascaris acus larvae from the inner organs and intestine of roach (rutilus rutilus) were studied in 4 lakes of differing water quality and pollution level in central finland between august 1985 and november 1986. the influence of r. acus larvae on the liver and pancreatic tissues of roach was examined histologically in additional material from 1989 and 1990. the inner organs of roach were most heavily infected with r. acus in the eutrophic, polluted ...19948026896
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