Ecological status of benthic communities associated to mussel farms in South of Chile: Can it be predicted using AMBI?

Abstract

One hundred percent of the blue mussel farm production in 2021 took place in the administrative region of Los Lagos, Chile. Despite the spatial concentration of this activity, there are no studies evaluating the environmental impact where farms are operating. This study integrated various approaches to assess soft-bottom areas in which two farms with different productions, culture systems, and maintenance routine were operating in Reloncaví Sound during the period May 2012-May 2013. One of the approaches used was the AZTI’s Marine Biotic Index (AMBI). Modelled AMBI values, prior to the survey (in 2011), showed that the sites were moderately to heavily impacted. A reduction of the mussel biomass production allowed the sites to improve their ecological status, according to estimated AMBI values (slightly disturbed). The comparison of current and predicted AMBI values, under the mussel biomass existing during the survey, suggests the model could be used for further evaluations and environmental impact studies, prior to a larger validation. Shells, mussels, and farm structures on the bottom promoted sea urchin-dominated communities. Their absence or a reduced presence promoted the presence of scavengers.