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

Conclusion The findings of this assessment contrast with previous socioeconomic analyses of OA effects on fisheries. In previous assessments of OA impacts [11–17], projected changes in fisheries have been presented almost exclusively as declines in potential landings with subsequent impacts on societies and economies. However, the majority of these studies investigated OA impacts in isolation from other facets of climate change and did not account for potential multi-stressor impacts. This study demonstrates that accounting for additional environmental factors can allow for different, and potentially more representative, narratives to emerge. Future management decisions and mitigation plans could be better informed through analyses which account for a more complete range of future effects on resource accessibility. Atlantic Canada is a region with an exceptionally high dependence on OA-susceptible fish- eries. However, the findings presented here suggest that OA-driven declines in the region will be minor compared to temperature-driven changes in future landings (Fig 6). Nonetheless, fisheries resources in Atlantic Canada are expected to see some notable redistributions under OA and climate change over the coming century. As observed in global-scale studies this is expected to result in ‘winners and losers’ with respect to access to future fisheries [e.g., 40]. It may be tempting to view the ‘winners’ as gaining access to new production. However, it is essential to recall that perceived increases come at a cost to other regions [68]. Additionally,

while OA effects may appear to be locally overwhelmed by temperature driven increases this should be considered in context and interpreted as limiting potential gains, and exacerbating declines. Within the Atlantic Canadian region, management plans should be developed that take cli- mate change and shifting species distributions into account. These plans should specifically address future allocation of resources when long-held access to certain high value fisheries (e.g., American lobster) might transition into new jurisdictions. Moreover, these consider- ations need to be extended to cooperative management of marine resources between nations. For example, net gains in Atlantic Canada may come at a cost to US states to the south. Management plans seeking to account for changing access to resources will benefit from assessments, such as in this study, which address how and where biological changes are likely to affect human communities, and where efforts are needed to mitigate these impacts. Supporting information S1 Note. Additional details for DBEM. (PDF) S2 Note. Details inclusion of ‘inshore’ and ‘offshore’ fleets and special cases regarding data availability. (PDF) S1 Table. DBEM projected relative change from individual climate models for each climate scenario and both future time-steps for each species. (ODS) S2 Table. data sources for crew size estimates. (PDF) S3 Table. Annual landing value (year 2000 dollars) and weights (tonnes) for marine species in Atlantic Canada. Values for DFO fisheries species groups (finfish, groundfish and shellfish)

are presented, as well as values for individual shellfish species. (ODS) OA and climate change impacts on Atlantic Canadian fisheries PLOS ONE | https://doi.org/10.1371/journal.pone.0226544 January 10, 2020 25 / 29