Environmental Impact of Sea Bass Cage Farming in the North Adriatic Sea

Abstract

"The main objective of the research was to reduce the organic and nutrient load under the net pen fish farms. An experiment was conducted to study the effects of artificial barriers fixed under a set of sea cages in order to reduce the environmental impact. The artificial barriers were made of four submerged galvanized steel pipes coated with plastic and placed on the sea floor (10 m depth) in the Trieste gulf. The experimental design was as follows: control (C), cages with barriers (B), cages without barriers (WB). Measurements were taken on the surface as well as at 4 and 8m of depth. The trial lasted from the end of June 2000 to December 2001. Water quality parameters were not significantly influenced by the fish cages. Surface samples were characterised by lower levels of salinity and higher levels of oxygen and nitrate compared to those taken at 4 and 8 m. The artificial barriers favoured the establishment of a rich epiphytic fauna that took advantage of the presence of organic matter derived from fish cages. The two species Nucula nucleus and Neanthes caudata and the total bacterial counts were identified as potential indicators of pollution under the fish cage farms."