Abstract
A trematode was frequently found in the stomach of the flatfish larvae under culture in the Niigata Prefectural Center of Cultural Fisheries. Preliminary culture experiments using different kinds of zooplanktons as feed were done to know the source of infection of the trematoda.
The trematoda occurred frequently in the larvae given marine copepods collected from the coast sea, but was never found in the larvae given cultured Artemia and Tigriopus. In most infected fishes the number of the trematoda per fish was 5 to 7. The trematoda was indentified as a member of the genus Uteroversiculus.
