Benthic recovery after the cessation of a gilt-head seabream, sparus aurata, farm in the Mediterranean sea

Abstract

[EN] An environmental recovery study was carried out after the cessation of a gilt-head seabream farm off the Mediterranean coast of Spain. Physicochemical variables of sediments, in situ benthic fluxes of oxygen and nutrients, and benthic macrofauna were measured in the farming area and at a control station. Five sampling campaigns were done, one before the closure and the others at 1, 3, 9, and 24 mo after cessation. Benthic flux of ammonium was the first variable to recover, followed by benthic fluxes of phosphate and dissolved oxygen and percentage organic matter in the sediments, which 3 mo after the cessation of farming already showed levels similar to those in the control station. Nine months after cessation, the other abiotic variables of the sediments disturbed by the activity had recovered, such as percentage coarse fraction, total phosphorus concentrations, and redox potential measurements. The recovery of the macrofauna was slower than the abiotic variables. Three months after cessation, Capitella capitata abundance had reduced drastically in the farming area, but similar specific richness levels were not observed between the two sampled zones until 2 yr after farming cessation.