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Sammanfattning

In the Northeast Atlantic, the International Council for the Exploration of the Sea (ICES) provides scientific advice under the precautionary approach (PA) and maximum sustainable yield (MSY) principles. F-MSY, the exploitation level that achieves MSY in the long term, is derived in ICES through stochastic simulations with the software EQSIM for most of the stocks. The computed F-MSY is then conditioned on the PA such that fishing at F-MSY does not exceed a 5% probability of the spawning stock biomass falling below the limit reference point B-lim. We compared reference points estimated using EQSIM and a short-cut management strategy evaluation (MSE) tool (RPETool), which approximates a full-feedback control loop, and, differently from EQSIM, mimics the stock assessment advice process, including all data lags, and retains the original structure of the assessment model. Here, we showed that the simplifications of the management system and the assessment model, which are necessary for conducting simulations with EQSIM, result in the breaching of the PA for 3 of 4 recently benchmarked stocks. For the only stock for which the PA was not violated, the EQSIM estimate of F-MSY was still larger than the actual F-MSY estimated within the assessment model, and long-term yields were not maximized. Considering that EQSIM has been used since 2017 to derive reference points in ICES for more than 75% of the data-rich stocks, it is urgent that it is phased out and substituted by a more appropriate approach, like RPETool. Furthermore, the analysis highlights the asymmetry between increased risk of breaching B-lim when fishing at or above F-MSY and low risk in terms of the minimal loss in long-term yield when fishing below F-MSY, with <5% yield loss even if F were reduced to around 60% of F-MSY. Considering the wide ranges of additional uncertainties about the assessment model and the associated F-MSY estimate, we propose that it is time for a paradigm shift within ICES to advocate for F-MSY being the upper limit for advice on fishing opportunities rather than the target.

Nyckelord

ICES advice framework; reference points estimation; management strategy evaluation; MSY

Publicerad i

ICES Journal of Marine Science
2025, volym: 82, nummer: 11, artikelnummer: fsaf204

SLU författare

UKÄ forskningsämne

Fisk- och akvakulturforskning

Publikationens identifierare

  • DOI: https://doi.org/10.1093/icesjms/fsaf204

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/144729