“…The Nerbioi's recovery has been gradual, responding to three milestones (Borja et al, 2010a): (i) in 1990, the implementation of the Wastewater Treatment Plant (WWTP) of Galindo, with physical and chemical treatments; (ii) in 1996, the closure of the highly polluting iron and steel industry "Altos Hornos de Vizcaya" (AHV); and (iii) in 2001, the addition of the biological treatment in the WWTP. The closure of industries, the WWTP implementation, and the limitations imposed by more restrictive environmental policies caused a decline of metals, organic compounds and fecal pollution inputs into the estuary, reducing the pollutant concentrations in estuarine waters and sediments (Belzunce et al, 2004b,a;García-Barcina et al, 2006;Borja et al, 2016;Irabien et al, 2018). This resulted in the recovery of, among others, benthic communities (Borja et al, 2006) and demersal fishes (Uriarte and Borja, 2009), as reflected in the increase of the general biological value within the estuary (Pascual et al, 2012).…”