Seasonal feeding of carp, Cyprinus carpio, in the Bay of Quinte watershed, Ontario

Observations from three areas and three seasons in 1977-78 suggest that carp (C. carpio ) resident in the waters of the Bay of Quinte watershed are omnivorous, but primarily ingest invertebrate organisms. Feeding is curtailed but does not cease during the autumn and winter months. Plant materials make up a small part of digestive tract contents in the fall, changing to seeds in the winter. The presence of considerable debris during summer and fall suggests an active scouring of the substrate during feeding. A low incidence of plant materials in the digestive tract contents at any time of the year indicates a low nutritional dependence on aquatic plants. This suggests that, at present population densities, carp are not a threat (in terms of direct ingestion) to indigenous aquatic plants though they may still act the role of a control species for many native macrophytes.