International Council for the Exploration of the Sea
Workshop on Scallop Aging (WKSA).pdf (2.04 MB)

Workshop on Scallop Aging (WKSA)

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posted on 2020-06-22, 00:00 authored by ICESICES

The ICES Workshop on Scallop Aging (WKSA) seeks to review and compare current scallop age reading methodologies, standard operating procedures and quality assurance processes across member institutes and collaborate to develop best practice. Assessments utilising age-based models need reliable age reading. Previous WGScallop age determination exchange results indicated inconsistencies within and among exchange participants and institutes. The workshop therefore aimed to understand these differences, identify consensus, and improve accuracy and agreement across institutes when aging shells. During the workshop, the institutes shared expertise and methodologies to develop understanding, agree standard principles and consensus aging for reference sets, appraise the potential use of SmartDots and discuss future exchange programmes.

The group provided insights in the field of age-determination across geographic scallop fisheries and stocks, with agreement that the aging method utilised reflected shell morphological traits and the visibility of annuli. A set of standard principles was established which lists agreed com-mon attributes that would provide baseline information and standard terminology across institutes. Microscope aging was identified as an essential technique for aging shells presenting challenges to age or quality check by eye with a number of institutes concluding that they would look to include microscopes in future as part of their quality assurance. The group agreed that microscope age training would be a beneficial part of a further workshop, proposed for 2021.

Consensus aging that included both visual and microscope techniques reduced variation in age determination and the group agreed that consensus aging was required to produce a reference set for each institute. ToR d), starting a consensus reference collection has been carried over to next meeting of WKSA. At present, WKSA do not recommend attempting another shell aging exchange until reference sets have been consensually agreed upon.

Smartdots has been initially investigated for its potential use in scallop shell aging as part of ToR c), however there is further work to do on this to fully test the usability of the software for future aging exchanges and ager training. WKSA will provide feedback to the Working Group on Bio-logical Parameters (WGBIOP).

This workshop initiated a regular platform to progress information flow and development of a cohesive understanding of shell aging across diverse fisheries, stocks and populations, vital for use in fisheries stock assessments and informing any future ecosystem-based fisheries management. To allow further exchange of best practice, microscope age training and consensus-aging of reference sets, the group agreed that a further workshop is recommended in 2021.


Published under the auspices of the following ICES Steering Group or Committee


Published under the auspices of the following ICES Expert Group or Strategic Initiative



ICES Scientific Reports





Contributors (Editors)

David Palmer; Karen Vanstaen

Contributors (Authors)

Lynda Blackadder; Isobel Bloor; Matthew Coleman; Adam Delargy; Peter Duncan; Eric Foucher; Peter Gibson; Ellen Sofie Grefsrud; Shona Kinnear; Claire Lambden; Roger Mann; James McArdle; Carrie McMinn; David Palmer; Charlotte Reeve; David Rudders; Claire Szostek; Adrain Tait; John Turriff; Karen Vanstaen; Julia Wouters



Recommended citation

ICES. 2020. Workshop on Scallop Aging (WKSA). ICES Scientific Reports. 2:57. 43 pp.

Publication language

  • en

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  • PDF



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