ICES WKARMAC2 REPORT 2018 Reports/Expert...آ  2019-03-01آ  ICES WKARMAC2 REPORT 2018 | 3 2 Agenda and

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  • ICES WKARMAC2 REPORT 2018

    ECOSYSTEM OBSERVATION STEERING GROUP

    ICES CM 2018/EOSG:32

    REF. ACOM, SCICOM & WGBIOP

    Report of the Workshop on Age

    Estimation of Atlantic Mackerel

    (scomber scombrus) (WKARMAC2)

    22–26 October 2018

    San Sebastian, Spain

  • International Council for the Exploration of the Sea

    Conseil International pour l’Exploration de la Mer

    H. C. Andersens Boulevard 44–46

    DK-1553 Copenhagen V

    Denmark

    Telephone (+45) 33 38 67 00

    Telefax (+45) 33 93 42 15

    www.ices.dk

    info@ices.dk

    Recommended format for purposes of citation:

    ICES. 2019. Report of the Workshop on Age Estimation of Atlantic Mackerel (scomber

    scombrus) (WKARMAC2), 22–26 October 2018, San Sebastian, Spain. ICES CM

    2018/EOSG:32 . 96 pp.

    The material in this report may be reused using the recommended citation. ICES may

    only grant usage rights of information, data, images, graphs, etc. of which it has own-

    ership. For other third-party material cited in this report, you must contact the origi-

    nal copyright holder for permission. For citation of datasets or use of data to be

    included in other databases, please refer to the latest ICES data policy on the ICES

    website. All extracts must be acknowledged. For other reproduction requests please

    contact the General Secretary.

    This document is the product of an Expert Group under the auspices of the Interna-

    tional Council for the Exploration of the Sea and does not necessarily represent the

    view of the Council.

    © 2018 International Council for the Exploration of the Sea

  • ICES WKARMAC2 REPORT 2018 | i

    Contents

    Executive summary ................................................................................................................ 1

    1 Terms of reference ......................................................................................................... 2

    2 Agenda and participation ............................................................................................. 3

    3 Update on known changes to the biology of mackerel .......................................... 4

    4 Review information on age estimations, otolith exchanges, workshops and validation work (ToR a) ........................................................................................ 6

    4.1 Exchanges and Workshops ................................................................................. 6

    4.2 Validation work .................................................................................................... 8

    5 Resolve interpretation differences between readers and laboratories; most recent exchange and workshop exercise (ToR b) ........................................... 9

    5.1 Pre-workshop exercise ......................................................................................... 9

    5.2 Workshop exercise: WKARMAC2 calibration exercise ................................. 11

    5.2.1 Material and methods ........................................................................... 12

    5.2.2 Results ..................................................................................................... 13

    5.2.3 Conclusions and evaluation of the exercise ....................................... 15

    5.3 Small exchange with Norwegian otoliths. A little experiment..................... 16

    5.3.1 Introduction ............................................................................................ 16

    5.3.2 Material and methods ........................................................................... 16

    5.3.3 Results ..................................................................................................... 18

    5.3.4 Conclusions and recommendations .................................................... 19

    5.4 Recommended actions for resolving interpretation differences between readers .................................................................................................. 20

    6 Resume of the studies of the formation of the growth zones in otoliths of different distribution areas presented during the workshop ......................... 21

    7 Compilation of an agreed manual for age estimation of mackerel (part of ToR e) ........................................................................................................................ 25

    7.1 Introduction ......................................................................................................... 25

    7.2 Methods and preparation .................................................................................. 25

    7.3 Agreed criteria for ageing mackerel ................................................................. 29

    7.3.1 Viewing the otoliths .............................................................................. 29

    7.3.2 Age determination criteria .................................................................... 30

    7.3.3 Other available information ................................................................. 32

    7.3.4 Otolith interpretation ............................................................................ 32

    7.3.5 False or Split Rings ................................................................................ 32

    7.3.6 Factors affecting annual ring formation ............................................. 33

    8 Collation of a set of agreed age otoliths (part of ToR e) ....................................... 34

  • ii | ICES WKARMAC2 REPORT 2018

    9 Recommendations for further cooperation, exchanges, workshops and other actions in relation to the age estimation of Mackerel (part of ToR

    e) ...................................................................................................................................... 35

    9.1 General recommendations ................................................................................ 35

    9.1.1 Manual..................................................................................................... 35

    9.1.2 Standardised reading within laboratories (section taken from last workshop report, WKARMAC 2010). ................................ 35

    9.1.3 Quality control between labs. ............................................................... 37

    9.1.4 Regular workshops ................................................................................ 37

    10 References ..................................................................................................................... 38

    Annex 1: Agenda ................................................................................................................... 40

    Annex 2: List of participants............................................................................................... 43

    Annex 3: Recommendations ............................................................................................... 44

    Annex 4: Contributions to the Workshop. Presentations and Working

    Documents. ................................................................................................................... 45

    Annex 5: Figures and Tables of the WKARMAC2 calibration exercise. .................... 46

    Annex 6: Figures and tables of the Small exchange with Norwegian otoliths.

    ......................................................................................................................................... 64

    Annex 7: Report of the Pre-WKARMAC2 exercise (Scomber scombrus). ................... 65

  • ICES WKARMAC2 REPORT 2018 | 1

    Executive summary

    A Workshop on Age Reading of Atlantic mackerel (Scomber scombrus) otoliths were recom-

    mended by WGBIOP 2015 to be carried out in 2016-2017. Due to the difficulty of finding a chair

    time passed and the workshop was recommended again by WGBIOP 2017 to be carried out in

    2018. This workshop (chaired by Jens Ulleweit, Germany, and Rosario Navarro, Spain), was

    held in San Sebastian (Spain) on 22–26 October 2018. 12 European countries took part in this

    workshop (Portugal, Spain, The Netherlands, Germany, Denmark, Norway, UK, Ireland, Faroe

    Islands, Iceland, Greenland and Greece), with a total of 23 participants from 14 laboratories.

    Most ICES Divisions of Northeast Atlantic mackerel distribution were analysed, as well as a bit

    of the Mediterranean Sea.

    The workshop achieved quite a lot in terms of ironing out, through on-screen discussion of

    difficult and/or old otoliths and calibration, some of the differences in age interpretation be-

    tween readers. Last workshop (WKARMAC 2010) ageing guidelines were revised and the mod-

    ifications agreed between the participants. The participants agreed to employ the revised

    ageing guidelines in their age estimations.

    The overall result of the workshop exercise shows an improvement in the agreement between

    readers (66.8% agreement, 31.4% CV), and especially Expert readers (73.2% agreement, 16.4%

    CV), regarding the exercise carried out before the workshop, which shows the usefulness of the

    on-screen discussion of difficult otoliths previous to the workshop exercise. However, the

    agreement between readers for otoliths with older ages (from