The parasitism of fish from Lake Constance--a comparison of present and earlier data

Commercial fish (perch, roach, bream, dace, and burbot) were caught below Langenargen in 1988-1990. Their infestation with cestodes and digenean trematodes was studied. The results were compared with earlier data. The infestation of perch with Diplostomum spathaceum and Ichthyocotylurus variegatus noted in 1988-1990 had increased as compared with that observed in 1974-1976. The infestation of perch with Triaenophorus nodulosus seen in 1990 had increased as opposed to that noted in 1988. The infestation of bream with D. spathaceum and of perch and roach with Tylodelphys clavata observed in 1988-1990 had remained the same as that seen in 1974-1976. The infestation of perch with D. spathaceum noted in 1988-1990 had decreased as opposed to that reported for 1974-1976. The infestation of bream, dace, and burbot with T. clavata noted in 1988-1990 had decreased as compared with that observed in 1974-1976. The infestation of perch with T. nodulosus seen in 1988/1989 had decreased as opposed to that noted in 1974-1976. All three cyprinids studied as well as the burbot had been less intensively infested in 1988-1990 than in 1974-1976. Only perch had been more intensively infested in 1988-1990 than in 1974-1976, especially with D. spathaceum and I. variegatus.