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

Abstract

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 eight 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. Based on our analysis of the data, we divided the farming regions into four sub‐regions with distinctive oceanographic properties and superimposed the sea surface warming trend and a spatial pattern of mortality by respective cause. 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 concentrations were more exposed, which in some cases coincided with higher sensitivity and lower adaptation capacity. Our models of four management scenarios allowed us to explore the changes in vulnerability associated with a southward movement of salmon production towards the Magallanes region. By identifying new protocols to increase adaptation and reduce vulnerability in a spatially explicit fashion, we provide policy recommendations aimed at increasing climate change adaptation and the long‐term sustainability of the sector.

Main issues and challenges for sustainable development of salmon farming in Chile: a socio‐economic perspective

“…It has also been suggested that the main impact from climate change to the Chilean salmon industry could come from the rise of salinity in estuarine areas, which could affect salmon productivity and mortality (Gobierno de Chile , Soto et al . ; this special issue).…”

Environmental issues in Chilean salmon farming: a review

“…Some water bodies such as the Reloncaví estuary have a very large number of farms which generate risks for salmon production and for the ecosystem (Soto et al . ). As water bodies capacities are estimated individually (site by site) and not in broader spatial scales, no sound estimates of carrying capacity at fjords/channels scale are available.…”

“…Between 2011 and 2016, approximately 32% of marine fattening farms were located in sites strongly influenced by freshwater, brackish waters and estuaries (Soto et al . ). For the near future, General Circulation Models (GCM) forecast a reduction in precipitation in northern Patagonia (Garreaud ), which could favour sea louse proliferation.…”

“…Furthermore, according to Soto et al . (), considering the accumulated salmon production from 2006 to 2017 in the main communities where they are farmed in southern Chile, the total N load varied between 77 and 2 tons per km 2 of relevant area (area of influence under the “salmon farming concessions grouping” (ACS) or “neighbourhoods” per community). Cochamó in Los Lagos (X) region, one of the oldest and densest salmon farming areas, has received the highest N load, while Río Verde in the southern most Region of Magallanes, the newest salmon area with lower aggregation of farms, has received the lowest load (Fig.…”

“…Figure redrawn from Soto et al . (), figures on production per commune were estimated from public information provided by the Chilean National Fisheries and Aquaculture Service ( SERNAPESCA ). () Annual average biomass, () Nitrogen loading.…”