Experimental infection of Atlantic salmon (Salmo salar) with marine Eubothrium sp (Cestoda : Pseudophyllidea): observations on the life cycle, aspects of development and growth of the parasite

The life cycle of marine Eubothrium sp. (Cestoda: Pseudophyllidea), from At lantic salmon (Salmo salar, L.) was experimentally completed in one year an d included only one intermediate host (Acartia tonsa Dana) (Copepoda: Calan oida). Adult cestodes were collected from farmed salmon, and ripe eggs rele ased by the cestodes were fed to Acartia tonsa. Ingested eggs hatched in th e gut and the larvae developed in the haemocoel of the copepod for 15 days at 16 degreesC. A total of 170 seawater-reared salmon were exposed to infec ted copepods and the total prevalence of Eubothrium sp. in the salmon after infection was 95.3%, with a mean intensity of 15.0 (range 1-87). The infec ted salmon were kept in the laboratory where the growth of the cestodes was studied for eleven months. Mean length of the cestodes increased with time , but a large variation among the cestodes was observed. Growth and maturat ion of the cestodes were dependent on host size and the number of worms pre sent in the intestine. No evidence of mortality of Eubothrium sp. was obser ved during the experimental period.