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

Impact index scores. Potential impacts from OA and climate change are anticipated to be highest where high exposure and high vulnerability coincide [17,18,57] (Table 5). Since there was only a single vulnerability score for each province, while the exposure was represented by a quartet of scores, the patterns within a given province’s quartet of index scores mirrored the patterns in the exposure: 2090 generally had higher potential impacts than 2050. Under the RCP 2.6 scenario the index scores tended to be higher due to more exaggerated gains in land- ings (and hence lower potential for impact) projected under RCP 8.5. The index scores coin- ciding with exposure to the Maritime management area (NB-mar and NS-mar) were the exceptions to this and had much higher potential impacts under RCP 8.5 (Table 5). Relatively high exposure scores were only achieved for the two provinces that have fisheries in the Maritime management area (i.e., NS and NB). Within these, NS had fairly low vulnera- bility scores, while NB scored mid-range in vulnerability (Table 5). The highest single exposure score was anticipated for 2090 under the RCP 8.5 climate scenario (Tables 2 and 5). The effect of this exposure treatment was strong enough that NB-mar and NS-mar scored the two highest potential impact scores. However, the low vulnerability in NS offset the exposure for the remaining Maritime management area quartet, and the remainder of the NS-mar impact scores were ranked low to minimal potential impact (Table 5). The higher vulnerability in NB

meant the province was more directly influenced by the exposure indicator and consequently ranked high for potential impact in three of the four of exposure scenarios (Table 5). Due to the occurrence of high vulnerability and moderate exposure, the NL index quartet ranked high to moderate, with the RCP 2.6 climate scenario exposures scoring higher than the unmitigated scenario (RCP 8.5) (Table 5). The remaining provincial units (NB-gulf, NS-gulf, PEI, and Que) were all adjacent to the Gulf management area and therefore had very low normalised exposure scores (Table 5). PEI mainly ranked in the moderate potential impact category due to high vulnerability, with only the 2050 –RCP 8.5 exposure ranking as low potential for impact (Table 5). The gulf sub-divi- sions of NB and NS (NB-gulf and NS-gulf) ranked from low to least potential for impact. Out Table 5. Impact index components and scores. Components are presented as final normalised scores. The exposure scores are presented in columns 3–4 as quartets of climate scenario and future time-step. The vulnerability scores (column 5) are the average (i.e., equally weighted combination) of sensitivity (Table 3) and adaptive capacity (Table 4) as indicated by Fig 4. The final index score quartets (column 6–7) are the average (i.e., equally weighted combination) of the relevant exposures and vulnerabili- ties. The final two columns indicate rank for each unique potential impact score: 1-high, 2-moderate, 3-low, 4-minimal and 5-least potential for impact (all categories

except 3-low, represent 6 unique scores– 3-low only represents 4 unique scores). Province RCP Exposure 2050 Exposure 2090 Vulnerability Impact 2050 Impact 2090 Impact Ranking NB-gulf 2.6 0.05 0.09 0.47 0.26 0.28 4 3 8.5 0.00 0.06 0.24 0.27 4 4 NB-mar 2.6 0.32 0.42 0.40 0.44 2 1 8.5 0.48 1.00 0.48 0.74 1 1 NL 2.6 0.15 0.17 0.75 0.45 0.46 1 1 8.5 0.10 0.02 0.42 0.38 2 2 NS-gulf 2.6 0.05 0.09 0.23 0.14 0.16 5 4 8.5 0.00 0.06 0.12 0.15 5 4 NS-mar 2.6 0.32 0.42 0.28 0.33 4 3 8.5 0.48 1.00 0.36 0.62 3 1 PEI 2.6 0.05 0.09 0.73 0.39 0.41 2 2 8.5 0.00 0.06 0.36 0.39 3 2 Que 2.6 0.05 0.09 0.12 0.08 0.11 5 5 8.5 0.00 0.06 0.06 0.09 5 5 https://doi.org/10.1371/journal.pone.0226544.t005 OA and climate change impacts on Atlantic Canadian fisheries PLOS ONE | https://doi.org/10.1371/journal.pone.0226544 January 10, 2020 20 / 29