Observations on the development of Syncuaria squamata (Nematoda: Acuariidae), a parasite of cormorants, in the intermediate and paratenic hosts.

The development of the nematode Syncuaria squamata (Linstow, 1883), a gizzard parasite of cormorants, was experimentally studied in the ostracod Notodromas monacha. After the eggs of this nematode have been swallowed by the ostracod, the toothed first-stage larvae of the parasite are released and penetrate through the intestinal wall into the haemocoel of the crustacean. Before attaining the infective third stage, the larvae moult twice in the body of the intermediate host (9-11 and 13-15 days after infection at water temperatures of 20-22 degrees C). The fishes Alburnoides bipunctatus, Noemacheilus barbatulus, Oncorhynchus mykiss and Poecilia reticulata were for the first time recorded as suitable experimental paratenic hosts of S. squamata third-stage larvae in which a slight growth of larvae may occur. The first recorded natural paratenic host of this nematode was tench, Tinca tinca, originating from a South-Bohemian pond where cormorants occur. Paratenic hosts are apparently the main source of S. squamata infection for cormorants.