Report of the Study Group on the evaluation of assessment and management strategies of the western herring stocks (SGHERWAY)

The ICES Study Group on the evaluation of assessment and management strategies of the western herring stocks [SGHERWAY] met in Aberdeen, UK, from 7-11 Decem-ber 2009. The chair was Emma Hatfield (UK) and 8 people in total attended, from five nations. The report addresses the ToRs, in turn, and discusses the work required to allow us to produce a set of full results for the deliberation of ACOM in July 2010. During the meeting, progress was made towards determining the best settings for the combined assessment of the three herring stocks (VIaN, VIaS/VIIb,c and VIIaN). The dataset was updated fully and a number of different assessment runs were carried out to explore the combined dataset. The selection on the oldest age, the reference age and a number of data combinations using different surveys and ages were explored. It was found that the only way to improve the retrospective pattern is to remove sur-vey years prior to 1998. The VIaN assessment uses all ages and all years in the VIaN survey time-series. Further work is still required here and there is no basis, as yet, from which to offer advice from the combined assessment.