Meiofauna as indicator for assessing the impact of fish farming at exposed marine site

This study aimed to detect the impact of organic loads due to biodeposition from a fish farm in anexposed area of the Strait of Sicily, Mediterranean Sea. Sediment chemistry and meiofaunal assemblageswere investigated on a seasonal basis at four stations: two from the impacted area and two controlstations. The presence of the cages induced a significant accumulation of proteins, lipids and biopolymericcarbon, resulting in a reduction in meiofaunal density at the impacted stations. Changes in communitystructure were also evident, as meiofauna under the cages were characterized by increased importance ofpolychaetes and copepods in comparison with a much lower importance of gastrotrichs and kinorynchs.Moreover, biodiversity decreased beneath the cages due to the disappearance of taxa more sensitive toorganic accumulation. This finding allowed us to propose the ration of nematodes to kinorynchs as apossible, potentially interesting, indicator of fish farm biodeposition.