Shaping sustainable harvest boundaries for marine populations despite estimation bias

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  • Daisuke Goto
    Institute of Marine Sciences, Bergen
  • Jennifer A. Devine
    Institute of Marine Sciences, Bergen
  • Ibrahim Umar
    Institute of Marine Sciences, Bergen
  • Simon H. Fischer
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • José A. A. De Oliveira
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • Daniel Howell
    Institute of Marine Sciences, Bergen
  • Ernesto Jardim
    DG Joint Research Center, Italy
  • Iago Mosqueira
    DG Joint Research Center, Italy
  • Kotaro Ono
    Institute of Marine Sciences, Bergen
Abstract Biased estimates of population status are a pervasive conservation problem. This problem has plagued assessments of commercial exploitation of marine species and can threaten the sustainability of both populations and fisheries. We develop a computer-intensive approach to minimize adverse effects of persistent estimation bias in assessments by optimizing operational harvest measures (harvest control rules) with closed-loop simulation of resource-management feedback systems: management strategy evaluation. Using saithe (Pollachius virens), a bottom water, apex predator in the North Sea, as a real-world case study, we illustrate the approach by first diagnosing robustness of the existing harvest control rule and then optimizing it through propagation of biases (overestimated stock abundance and underestimated fishing pressure) along with select process and observation uncertainties. Analyses showed that severe biases lead to overly optimistic catch limits and then progressively magnify the amplitude of catch fluctuation, thereby posing unacceptably high overharvest risks. Consistent performance of management strategies to conserve the resource can be achieved by developing more robust control rules. These rules explicitly account for estimation bias through a computational grid search for a set of control parameters (threshold abundance that triggers management action, Btrigger, and target exploitation rate, Ftarget) that maximize yield while keeping stock abundance above a precautionary level. When the biases become too severe, optimized control parameters?for saithe, raising Btrigger and lowering Ftarget?would safeguard against a overharvest risk (

Keywords

  • decision-making, environmental stochasticity, fisheries management, management procedure, management strategy evaluation, measurement error, precautionary principle, retrospective pattern, risk analysis, state-space model, stock assessment, trade-offs
Original languageEnglish
Article numbere3923
JournalEcosphere
Volume13
Issue number2
Early online date6 Feb 2022
DOIs
Publication statusPublished - Feb 2022
Externally publishedYes
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