Potential socioeconomic impacts from ocean acidification and climate change effects on Atlantic Canadian fisheries

invertebrate species that rely on calcium carbonate shells and exoskeletons (e.g., corals, oysters, crabs) will likely express negative responses [3,4]. Low pH events, driven by upwelling and exacerbated by OA, have already impacted shellfish production in the Pacific Northwest of the United States and Canada [1–3,6–8]. Globally, seafood is a critical dietary component for over 3 billion people and is also a highly traded commodity [9,10];changes in production could therefore have significant impacts for many and diverse communities. There is a body of emerging literature seeking to address how OA may affect human systems by linking projected biological responses to OA with ecosystem services such as fisheries production. To date, socioeconomic OA impact research has been undertaken at a range of scales and resolutions from international [11–13] to national [14–16] and sub-national [17]. These studies have generally focused on OA in isolation from other cli- mate change effects, and predicted declines in revenues and higher social risk in regions where shellfish fisheries are proportionally more important. Several previous assessments [e.g., 11,14,17], follow risk assessment frameworks to identify communities or regions that are most susceptible to impacts from OA. In these assessments risk is defined in conventions similar to that of the International Panel on Climate Change (IPCC) [18], and based on the socioeco- nomic structure of the social unit in question and the likelihood of an impact from OA.

In Canada, seafood production is concentrated on the Atlantic Coast, with over 80% of total landings and over 85% of the commercial fishing fleet based in the region [19]. Within Atlantic Canada, shellfish have become an increasingly important component of capture fish- eries, accounting for nearly 50% of regional landings by weight and over 75% of total landed value [20,21] (Fig 1). At the same time, Atlantic Canadian provinces and communities repre- sent some of the least wealthy segments of the Canadian economy, with most of the provinces being net recipients of federal equalization payments as well as receiving overall above average per capita federal support [22]. Furthermore, most of the provinces in the region have compar- atively rural populations, with many relatively small communities which are more highly dependent on employment from natural resource-linked sectors such as fisheries [23,24]. Given the high contribution of shellfish to total seafood production, together with the socio- economic background of the provinces in the region, Atlantic Canada presents a highly rele- vant setting for investigating how potential OA-driven changes in fisheries might affect human communities. In this paper, a biophysical model was linked with an impact assessment framework to investigate how OA and climate change might drive shifts in future availability of fisheries resources for Atlantic Canada, and which provinces in the region are most likely to be affected by these shifts. The assessment aims to highlight regions in Atlantic Canada where potential

impacts from OA and climate change is highest, under contemporary socioeconomic settings, given predicted changes in fisheries’ access. In the assessment framework OA and climate change are the sole drivers for changes in fisheries. Given the limits of scientific understanding and modelling capabilities more subtle, albeit important, factors such as potential for individ- ual species’ evolutionary responses to changing environmental conditions are not included. Methods Study area ‘Atlantic Canada’ typically refers to four Canadian provinces: New Brunswick (NB), New- foundland and Labrador (NL), Nova Scotia (NS) and Prince Edward Island (PEI). The prov- ince of Quebec (Que) also borders the Atlantic Ocean but it is often not included as part of ‘Atlantic Canada’ due to significant demographic and cultural differences. However, for the OA and climate change impacts on Atlantic Canadian fisheries PLOS ONE | https://doi.org/10.1371/journal.pone.0226544 January 10, 2020 2 / 29 (SSHRC) in the form of the Canadian Graduate Scholarship-Masters Program (CGS-M)- http:// www.sshrc-crsh.gc.ca/. TCT and WWLC also acknowledge support from the Social Sciences and Humanities Research Council of Canada (SSHRC) -http://www.sshrc-crsh.gc.ca/; and through the OceanCanada Partnership - https://oceancanada. org/. WWLC also acknowledges funding support from the Nippon Foundation-University of British Columbia Nereus Program - http://nereusprogram. org/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.