Benthic recovery after fish farming cessation: A “beyond-BACI” approach

• Published in: Marine pollution bulletin 2012-04, Vol.64 (4), p.729-738
• Main Authors: Aguado-Giménez, F., Piedecausa, M.A., Gutiérrez, J.M., García-Charton, J.A., Belmonte, A., García-García, B.
• Format: Article
• Language: English
• Subjects: Animals; benthic environment; Benthic recovery; benthic zone; Beyond-BACI; Ecosystem; Environmental Monitoring; farming systems; fish culture; Fish farming cessation; fish farms; Fisheries; Geologic Sediments - analysis; Geologic Sediments - chemistry; omnivores; phosphorus; Polychaeta; Polychaeta - physiology; Polychaete assemblage; redox potential; Seawater - analysis; sediments; Spatial–temporal variability; sulfides; water pollution
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2012.02.012

► Sediment variables were monitored before and after fish farming cessation. ► A beyond-BACI approach was developed to ascertain whether recovery occurred. ► One year after fish farming cessation, symptoms of chemical recovery were observed. ► Polychaete assemblage developed to a more structured and diverse assemblage. ► A partial recovery of the benthic recovery was achieved after 1year. The development of a benthic environment after fish-farming cessation was examined. To ascertain whether recovery occurred, several abiotic (granulometry, acid-volatile sulfides, total phosphorus and redox potential) and biotic (polychaete abundance) variables were monitored using a “beyond-BACI” approach. Before the cessation of farming, the geochemical conditions and polychaete assemblages differed among the impacted and control sites. After cessation, an improvement of the geochemical conditions was achieved. A significant tendency toward a recovery of the polychaete assemblage in the impacted area was observed, but significant differences still remained compared with the control sites. The acid-volatile sulfide level was responsible for these differences. The abundance of polychaete families associated with organically enriched sediments diminished at the impacted site after cessation, whereas the abundance of some sensitive and omnivorous families increased. The “beyond-BACI” approach provided a wider framework than other approaches, enabling us to differentiate the natural variability from those changes induced by the fish farm and farming cessation.