Trchodina sp.(Ciliophora:Peritrichida) in eel Anguilla anguilla in recirculation systems in Denmark:host-parasite relations

摘要

Farmed eel cultured in recirculation systems in Denmark were found infected by Trichodina jadranica Raabe, 1958. Associations between parasite abundance and fish size was examined in 2 different production systems. In one system, stocked with relatively well-nourished eels(3 to 31 g), most of the parasites(66%) were found on the dorsal part on the skin and relatively few were found on the gills(approx. 8%). The infection level was significantly positively correlated both with fish weight and length. In the other system, stocked with relatively malnourished small eels(0.5 to 4 g), significantly more parasites(0.06+-0.02[SD]) were present on fish with a low condition factor than on fish with a higher condition factor(0.13+-0.01[SD]). In this eel stock the vast majority of the trichodines were found no the gills.