MEPS 277:253-261 (2004)  -  doi:10.3354/meps277253

ABSTRACT: This study investigated the role of wild fishes associated with marine farms as potential consumers of organic waste in the water column and sediment. Experiments were carried out at a fish farm in a semi-enclosed bay in the Mediterranean Sea (SE Spain). Sediment traps collected organic waste from net-pens in the water column at different depths during June and July 2001 and benthic caging experiments were carried out on the sediment from October 2000 to January 2001. The experiment showed that about 80% of the particulate organic matter leaving the rearing net-pens may be consumed before it settles on the sediment. Significant changes in the nutrient quality of the organic matter exported are also due to consumption by wild fishes. Wild fishes thus play an important role in recycling the organic matter of the sediment, and regulate the benthic community structure. Our results indicate that the trophic role of wild fishes should be considered when evaluating the environmental impact of fish farms.

KEY WORDS: Aquaculture · Wild fishes · Fish farm · Sea-cage · Organic waste · Mediterranean Sea