Changes in trophic behaviour and trace metal concentrations in wild fish in a tuna-farming environment. The key role of a sound baitfish choice

摘要: Abstract It is essential from both the consumer perspective and environmental sustainability aspect, to delve more deeply into specific traits conditions of fish reared in a pisciculture setting. Among many factors that affect latter, one most important cycling chemical compounds intensive rearing systems. For this reason, we analysed stomach contents trace metal levels (cadmium, copper, chromium, lead, zinc) muscles several species aggregate around mid-Adriatic cages Atlantic bluefin tuna (Thunnus thynnus), attracted by organic leftovers found farmed waters. The metals were also samples tuna, used as feed (baitfish), their non-farm-associated counterparts. Finally, better follow dietary relationships metal-acquisition pathways, stable isotopes. results revealed wild consume great deal trophic resources deriving cages, mainly form baitfish remains. isotopes suggest high herring (Clupea harengus), there an increased level for omnivorous bogue (Boops boops), decreases carnivorous garfish (Belone belone). No significant differences concentrations detected between farm-associated fish, with exception zinc bogue, which lower specimens aggregating farm. Most importantly, (sardine, Sardina pilchardus, herring), (garfish bogue) did not exceed recommended limits established European legislation. However, cadmium values garfish, sardine close to, but over legal limit value. reasons behind these potential consequences should be further investigated, although only moderate degree concern regard content stocks captured area under study.