Nøttestad, Leif

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Advice from ICES on mackerel in the Northeast Atlantic for 2015 Presented by  Leif Nøttestad Principal scientist Advice for 2015 • ICES advises on the basis of the Norway, Faroe Islands, and EU management plan that catch in 2015 should be between  831 000 tonnes and 906 000 tonnes  • ICES advises that the existing measures to protect the North Sea spawning component should remain in place Stock status Fishing mortality in 2013 is estimated to be 0.22, below FMSY and FPA. Fishing mortality was above Flim during the early 2000s   The mackerel stock is in a very good state! Summary of stock assessment The shaded catches prior to 2000 are the years that have been down-weighted in the assessment due to considerable underreporting that is suspected to have taken place. The shaded recruitment value for 2013 is from RCT3 and the shaded recruitment value for 2014 is the geometric mean of 1990-2012. Top right: SSB and F over the years. The black dotted lines represent the 95% confidence intervals.  Scientific basis Quality considerations The assessment benchmarked in 2014 and the new assessment model was set up so that it takes into account the large uncertainty in historical catches prior to 2000. The assessment now uses an age-based state space assessment model (SAM), including new tuning series in addition to the egg survey index which provides an index of SSB.   Age disaggregated abundance indices are derived from the International Ecosystem Summer Survey in the Nordic Seas (IESSNS) (age 6+).  International Bottom Trawl Survey (IBTS) (age 0).  The model also incorporates tagging and recapture data for fish tagged at age 2. Tagging data are only used at present for the period 1980-2005.     ICES revisions on egg survey SSB time-series SSB estimates derived from the mackerel egg surveys for the combined survey area. The green line represents the input data for the mackerel assessment until   2012. The red spot is the estimate given by WGMEGS for the updated  advice. The blue line represents the agreed input data by WGWIDE 2014 Consequences of revised SSB fra egg survey • Higher SSB estimates in 1992 and 1995, in the order of  • 1 million tonnes, because not all areas were included, and  • 600 000 tonnes lower SSB estimates in 2013 due to errors in calculations.  • Consequences:  – Less variability in the SSB indices (flatter and less contrast),  – Lower SSB in 2014 from the analytical assessment. Historical assessment results The 2013 assessment is from the SAM model during WKPELA. There was no assessment in 2013, so results and historical perceptions on SSB, F and recruitment have changed significantly. Horizontal lines represent reference points (Blim, Bpa) and (Fmsy, Fpa, Flim) Reference points last changed in 2014 Outlook for 2015 Estimation of 2014 catch Management plan Stock-recruitment relationship Draft request on a revised long-term management plan evaluation A management plan was agreed by Norway, Faroe Islands and the EU in October 2008. ICES has evaluated the plan and concluded that is was precautionary (ICES 2008, 2014b). However, since 2009, there has been no international agreement on TAC. Advicing according to the new assessment using the management plan is still considered precautionary, even though the plan may no longer result in a long-term maximization of the yield.   EU, Norway and the Faroes have approached ICES with a draft request on a revised long-term management plan evaluation. ICES is currently carrying out analyses to answer this request draft. This work should provide the appropriate combination of Btrigger and fishing mortality range consistent with the precautionary approach and MSY objectives. Management plan harvest control rules from 2008 

Advice from ICES on mackerel in the Northeast Atlantic for 2015

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Advice from ICES on mackerel in the Northeast Atlantic for 2015

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