Kimoto, A.

Lauretta, M.

Mayor, C.

Ortiz, M.

Palma, C.

Rodriguez-Marin, E. (Enrique)

Rouyer, T.

Walter, J.

Zarrad, R.

English

Repositorio Institucional Digital del IEO

PRELIMINARY RESULTS OF THE 2022 VPA STOCK ASSESSMENT OF EASTERN ATLANTIC AND MEDITERRANEAN BLUEFIN TUNASCRS/P/2022/015T. Rouyer, A. Kimoto, R. Zarrad, M. Ortiz, C. Palma, C. Mayor, M. Lauretta, E. Rodriguez-Marin and J. WalterBFT DATA PREP MEETING 18-26/04/2020INITIAL MODEL SETUPNo new set-up was agreed on in 2020● 2022 Model setup = 2020 RUN 84 = 2017 base case (Run 0)The model specifications:● Age 10 as plus group● Maturity ogive (Ages 1-10): 0; 0; 0.25; 0.5; 1; 1; 1; 1; 1; 1● Constraint on vulnerability: penalty of 0.4 on the last 3 years for ages 1 to 9● No penalty on recruitment● No constraint on spawner-recruit relationship● Terminal Fishing mortality at age (1-9) of population freely estimated● F-ratio estimated by time blocks for 1968-1980, 1981-1995, 1996-2007 and fixed to one for 2008-2020.● Natural mortality (Ages 1-10): 0.38; 0.30; 0.24; 0.20; 0.18; 0.16; 0.14; 0.13; 0.12; 0.1● The variance scaling for the indices (i.e. weighting) freely estimated, but same variance for both Trap indices, same variance for the three Japanese longline indices, same variance for the two Baitboat indicesCONTINUITY: FIT TO CPUECONTINUITY: TRENDSCONTINUITY: Fratio estimatesCONTINUITY: RETROSPECTIVESCONTINUITY: RETROSPECTIVESCONTINUITY: JACKKNIFECONTINUITY: JACKKNIFEPATH FORWARDIndices● GBYP aerial to be included (which ones, how, same as WMED_LARV) ?● Update of WMED_LARV (included in MSE) ?Problems with Fratio -> instability● Try to lock values ?○ Try historical values (2017 assessment, 2014 assessment)○ Explore 1 and only estimate for 1996-2007 (VPA manual: typically the values are fixed to 1.0 unless there is some compelling biological reason to suggest otherwiseProblems with CAA (and specifically 1996-2006)● Sensitivity using CAA from SS3● Lock Fratio for the whole time period but for 1996-2006Explore wider age-structure● Extend to Age16+● Easier to assume Fratio=1● But modeling subgroup found it problematicThank you

SCRS/P/2022/015

Rodriguez-Marin, Enrique

Digital.CSIC

http://www.repositorio.ieo.es/e-ieo/bitstream/10508/16387/4/SCRS_P_2022_015_Rouyer_et_al_v2.pdf

SCRS/P/2022/015

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