Update on Canada’s analysis of balancing fisheries with the protection of vulnerable marine ecosystems
Canada fishes for sablefish in its national waters and a small part of the NPFC Convention Area in the northeast Pacific Ocean. We present a Canadian case study that illustrates how spatial trade-off analyses can help maintain socio-economic benefits of the sablefish fishery while promoting the conservation of vulnerable marine ecosystems (VMEs). First, we mapped the locations of potential VMEs (pVMEs) by developing species distribution models for six of Canada’s VME indicator taxa, including four cold-water coral orders (Alcyonacea, Scleractinia, Antipatharia, Pennatalucea) and two sponge classes (Hexactinellida and Demospongiae). We then developed a spatial footprint of sablefish fishing activity from annual sablefish landings (2006-2018) queried from Fisheries and Oceans Canada’s commercial catch databases. Using Marxan, a decision-support tool for marine spatial planning, we evaluated several trade-off scenarios by comparing the potential loss in sablefish landings when protecting pVME areas where Canada fishes for sablefish. Sensitivity analyses of our results indicate that if marine reserve size area was small in our scenarios (i.e. the Marxan boundary length modifier (BLM) was ≤10), there was no impact to sablefish landings regardless of whether analyses used recent (2014-2018) or included historic landings (2006-2018) data or individual versus multiple VME indicator taxa. Fisheries losses were only apparent in our sensitivity analyses when we prioritized larger marine reserve patch sizes (i.e. BLM ≥100); although the trade-off between loss in fishery landings and increased protection was non-linear. In our spatial planning scenarios where small marine reserve patch size was prioritized, we predicted that up to 25% of pVME areas could be protected with only a 1% loss to the fishery in terms of landings. Similarly, if 50% of pVME areas were protected, we would only expect a 10% loss in sablefish fishery landings. Our approach strives to balance protection of VMEs with the socio-economic interests associated with sablefish fisheries management within Canada’s EEZ and a portion of the NPFC Convention Area. We welcome input from NPFC members on how to proceed with our analyses and fisheries management decisions.