International Council for the Exploration of the Sea
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Workshop on Tools and Development of Stock Assessment Models using a4a and Stock Synthesis (WKTADSA)

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posted on 2021-04-19, 00:00 authored by ICESICES
This report summarises the work carried out during the Workshop on Tools and Development of Stock Assessment Models using a4a and Stock Synthesis (WKTADSA). It provides a brief description of the two assessment frameworks used and information on available re-sources to help the assessment scientist develop their stock assessment. Additionally, a brief overview of each of the case studies are provided with full documentation of the models and explorations presented in working documents at Annex 5.
The workshop brought together ICES stock assessors developing or working with Stock Synthesis (SS) and Assessment 4 All (a4a) with the method development experts of the two frameworks explored. The format of the meeting was split into two 5-day meetings with the first providing an introduction and overview of each of the frameworks, through presentations from the experts. This allowed for a much larger participation from the wider ICES community. The second meeting focused on the application of the two assessment approaches to develop the assessments of ten ICES stock units given in section 2 and Annex 4.
Both meetings gave valuable training, information, and support to participants with a wide and varied background in a4a and SS. Furthermore, the experts made themselves available to provide additional support during the intersessional period between meetings and prior to the first meeting being held, advancing the progress of each of the assessments being developed.
All ten case studies provided a first (base case) model for further development. Much progress was made during the workshop and between the two workshop meetings. Two assessments, megrim and sardine both in divisions 8.c and 9.a, were considered ready for an assessment benchmark, only requiring sensitivity analyses which could be carried as part of an assessment benchmark workshop.
To continue the tremendous progress made, similar workshops using the format of the second meeting, or informal meetings could be scheduled with the experts specific to the approach used to further prepare the assessments for benchmark workshops. Stock units considered close to completion were both black-bellied anglerfish, white anglerfish in divisions 7 and 8.a, b, d, fourspot megrim in divisions 8.c and 9.a and megrim in divisions 7.b-k and 8.a, b, d.
The other three stock units, both hake stocks and white anglerfish in divisions 8.c and 9.a required further exploration as well as reviewing of input data used in the assessment and would therefore require additional time before they would be ready for an assessment benchmark workshop.


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

  • FRSG

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



ICES Scientific Reports





Contributors (Editors)

Lisa Readdy

Contributors (Authors)

Esther Abad; Massimiliano Cardinale; Santiago Cerviño; Anne Cooper; Kathryn Doering; Jette Fredslund; Dorleta Garcia; Hans Gerritsen; Vladlena Gertseva; Ane Iriondo; Kelli Johnson Gwladys Lambert; Hugo Mendes; Richard Methot; Colin Millar; Iago Mosqueira; Teresa Moura Paz Sampedro; Andreia Silva; Cristina Silva; Agurtzane Urtizberea; Laura Wise



Recommended citation

ICES. 2021. Workshop on Tools and Development of Stock Assessment Models using a4a and Stock Synthesis (WKTADSA). ICES Scientific Reports. 3:33. 197 pp.