Fish harvesting advice under climate change: A risk-equivalent empirical approach

managed in a risk-based framework, expressing the impacts of climate or ecosystem, change in terms of risk associated with fisheries decision making is fully consistent with the existing par- adigm and this can facilitate the rapid incorporation of CC conditioned advice in manage- ment. The analytical approach proposed here focuses on the incremental uncertainty in stock production arising from a changing environment when quantifying the response of fish stocks to fishing pressure and the ability to achieve fishery management objectives, given a specific environment scenario. This uncertainty can be estimated regardless of the depth of detailed mechanistic understanding of stock productivity dependence on the environment even if the amount of that uncertainty might differ between approaches. Here we applied an EM method for developing climate-informed, risk-based science advice for a data-moderate fish stock in a rapidly changing environment. An EM approach allows us to take advantage of the available Fig 8. A contour plot showing how exploitation rate of the stock would need to be altered to condition advice for Gulf of St Lawrence Greenland halibut to changes in median bottom water temperature at 150 m depth. The climate impact is mediated through the relationship between the temperature and Greenland halibut production rate observed in the past. The contours represent the risk expressed as the probability of not achieving the target biomass objective (mean biomass from 1995–2000) after 10

years for different fishing and climate scenarios. For risk levels 50% and lower (shaded green), risk equivalent strategies are possible to compensate for CC by adjusting relative exploitation rate. The actual exploitation rate and temperature scenario is overlaid on the contours. https://doi.org/10.1371/journal.pone.0239503.g008 PLOS ONE Climate-change conditioned risk-equivalent fisheries advice PLOS ONE | https://doi.org/10.1371/journal.pone.0239503 February 19, 2021 16 / 22