The first results reported in this work deal with the origin and biology of organisms forming these aggregates, excluding biochemical and bacteriological aspects. A remarkable feature is the wide variety of both planktonic and benthic components in the collected matter. More than 111 taxonomic units have been so far identified. In addition to these elements of marine origin, these aggregates deposited on fishing nets also contain exogenous matter of continental origin, mainly Grey Willow Salix atrocinerea silk's seeds, mammals' hairs and pollen. In this work, particular attention is also given to the potentially irritating and stinging organisms present in the aggregates. Finally, hypotheses are developed about the aggregation process of these living organisms and their pelagic sedimentation induced by the presence of fishnets in the water column.