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Perceptions of the challenges for the provision of mackerel advice
- 1. Perceptions of the challenges for the provision of advice WKRRMAC, 8th May 2019 @DickeyCollas
- 2. Why provide advice? Article 5b of the UN Fish Stocks Agreement (1995) “ensure that such measures are based on the best scientific evidence available & are designed to maintain or restore stocks at levels capable of producing maximum sustainable yield,” “… decision-making based on best available scientific advice, broad stakeholder involvement and a long-term perspective.” EU CFP (2014) Norway Marine Resources Act (2008) “… a precautionary approach, in accordance with international agreements and guidelines”
- 3. Evidence providers need to be: • Relevant – giving suitable advice • Legitimate – considered appropriate • Credible – using accepted methods Processes must be transparent & accountable
- 5. Knowledge & risk The riskier you want to exploit, the more certain you need to be, & the more evidence you need.
- 6. Optimising yield: • Precautionary • Maximum sustainable yield • Stability in catches Impact does not threaten the ecosystem – as defined in the EU as good environmental status, and OSPAR/NEAFC standards (VME, Texel –Faial criteria).
- 7. What do we mean by uncertainty? XXXXXX
- 8. What do we mean by uncertainty? ENSEMBLE APPROACHES Anderson et al 2017 - Improving estimates of population status and trend with super ensemble models
- 9. Mackerel – history of advice changes 2013 Assessment method (ICA) rejected – historical catches uncertain Advice for 2014 based on precautionary approach (≤ 889,886 t) 2014 Benchmark - New assessment method (SAM) – down-weighed historical catch data, included swept area survey (IESSNS), IBTS and tagging data Advice for 2014 revised based on MP (927,000 – 1,011,000 t) Advice for 2015 based on MP (831,000 – 906,000 t) 2015 Advice for 2016 based on MSY (≤ 667,385 t) Advice in response to Coastal State request on LMP – reference points, Ftarget Advice in response to Coastal State request on management of mackerel - Frange 2016 Advice for 2016 revised (≤ 773,846 t) – IBTS recruitment index used incorrectly Advice for 2017 based on MSY (≤ 944,302 t) 2017 Benchmark, estimating lower SSB and higher F in recent years MSE of EU/Faroes/Norway management plan Advice for 2017 revised (≤ 857,185 t) – IESSNS index incorrectly calculated Advice for 2018 based on MSY (≤ 550 948 t) 2018 Downward revision of SSB in 2016 & 2017 but within confidence of 2017 assessment. Request for inter-benchmark as issues with model performance & tagging data. Advice for 2019 based on MSY (≤ 318,403 t)
- 10. How do we give advice that accounts for more realistic uncertainty? • Does one assessment model represent the truth? • Do MSE operating models express all the alternative states? • How can we build stability into the system? • Can we build a quality assured advice process that remains flexible to the quirks of nature and science?
- 11. We must be able to do better…