PROTIST TRANSPORT VIA BALLAST WATER - BIOLOGICAL CLASSIFICATION OF BALLAST TANKS BY FOOD-WEB INTERACTIONS

Ship's ballast waters and sediments serve as a vector in the transport ation of marine organisms, including toxic dinoflagellates, parasitic labyrinthulids and other potentially harmful species, These exotic org anisms have caused major ecological changes, as well as concern over e ffects an human health, fishing and aquaculture. Heterotrophic pratozo ans may be inadvertently introduced when their trophic or resting stag es are discharged with the ballast-tank waters and sediments, This sur vey describes the protist communities present in ballast tanks of carg o vessels arriving in Israeli Mediterranean Forts, 362 records of livi ng protozoan species, identified to at least 198 species belonging to 82 heterotrophic genera, were made in this study The tanks examined ex hibited a remarkable uniformity of protist communities, enabling us to classify food web interactions, ranging from bacteria-grazing protozo ans, predatory unicells, and more intricate associations including par asites and metazoans.