Salmon farming vulnerability to climate change in southern Chile: understanding the biophysical, socioeconomic and governance links

Here we describe an assessment of climate-change vulnerability for the salmon farming sector in southern Chile using a model that combines semi-quantitative measures of Exposure (risks), Sensitivity (economic and social dependence), and Adaptation Capacity (measures that prevent and mitigate impacts).  The evaluation was carried out in 8 pilot communes representative of salmon production (marine grow-out). Exposure was estimated with a semi-quantitative risk assessment tool based on oceanographic, meteorological and hydrological information, mortality-by-cause databases, and through extended consultation with experts and relevant stakeholders.  Threats included relevant changes in water temperature and salinity, declines in dissolved oxygen, occurrence of HABs, and diseases that could be associated with climate change. The combined analysis of information allowed us to divide the farming regions into four sub-regions with distinctive oceanographic properties over which the sea surface warming trend and the spatial pattern of mortality by cause were superimposed. Reduction of precipitation and the increase of air and sea surface temperature are the most relevant foreseen climate change drivers, especially for regions X and XI. The resulting vulnerability matrix indicated that communes with higher production concentration were more exposed, this in some cases coincided with higher sensitivity and lower adaptation capacity. Modelling with 4 management scenarios allowed us to explore the changes in vulnerability associated with a southward movement of salmon production towards the Magallanes region. By allowing the identification of key aspects to increase adaptation and reduce vulnerability in a spatially explicit fashion, we provide support to policy recommendations aimed at increasing climate change adaptation and sustainability of the sector.