In recent years a lot of progress of automated index calculation procedures and the adoption of a model-based indices, including combining several surveys into a single index (e.g. deltaGAM method), directly based on DATRAS exchange data, was made. While the automation benefits consistency and transparency it also makes implicit assumptions regarding data collection which are easy to forget when applying an automated procedure. Specifically the indices which are based on data from the different beam trawl surveys, which use different gears and apply different biological sampling designs, have to be thoroughly evaluated and contrasted to historical methods to understand the differences and their possible implication for stock assessment. We need to investigate what extent the new method affects the outcomes of the used stock assessment models in comparison with the previously used methods.
This automation of procedures to calculate survey indices unfortunately risks reducing the important communication between survey and assessment experts. A better understanding of the interactions of the survey and age sampling design with automated index calculation is necessary to ensure appropriate index and sampling design development.
Working Group on Beam Trawl Surveys (WGBEAM) organizes this two-day workshop to bring experts from survey and assessment groups together in order to address this issue. The results of this workshop will have implications for the used approaches to derive adequate survey indices and to make best use of the available survey data and are designed to feed into the benchmark procedures on a stock specific basis.WKICDAT takes place 21-22 March 2019 at the ICES HQ, Copenhagen, Denmark.