Report of the Workshop on the Analysis of the Benchmark of Cod in Subarea IV (North Sea), Division VIId (Eastern Channel) and Division IIIa (Skagerrak) (WKCOD 2011)

• Main Author: ICES (11907872)
• Format: Report
• Language: unknown
• Published: 2011
• Subjects: Fisheries and aquaculture; Greater North Sea (ICES Ecoregion); cod; Gadus morhua; WKCOD; benchmark analysis; CM 2011/ACOM; Norway; Iceland
• Online Access: https://doi.org/10.17895/ices.pub.19280867.v1

The ICES workshop on the analysis of the benchmark of cod in Subarea IV (North Sea), Division VIId (Eastern Channel) and Division IIIa (Skagerrak), WKCOD, met at the ICES headquarters (Copenhagen) during February 7–9, 2011. There were 19 participants from seven countries (Belgium, Denmark, Germany, Iceland, Norway, Spain, and UK), of which three participants were industry representatives and one was an external reviewer. The meeting was chaired by Einar Hjorleifsson (Iceland). The meeting was designed to serve as an inter-benchmark protocol for the North Sea cod assessment and was tasked with reviewing the input data used and the assess-ment model and settings, proposing changes to them if deemed appropriate. Additional work, if required, was also to be identified. A consensus of the data input, model assumptions and framework to be used in the 2011 cod assessment was reached at the WKCOD meeting. The conflict in the IBTS quarter 1 vs. quarter 3 surveys, an issue raised by the WGNSSK in 2010, was not fully resolved. The abundance indices in the quarter 1 survey were considered to more likely reflect stock trends in recent years, because of suspected changes in catchability in the quarter 3 survey in relation to recent changes in the spatial distribution of fish in the latter part of the year. It is recommended that further investigation be ad-dressed within a working group on improving use of survey data for assessment and advice (suggested ToRs are in WKCOD report). Additionally, using both surveys in the assessment results in trends in unallocated removals that go against the prevail-ing hypothesis that the bias in landings in particular and potentially in discards esti-mates in recent years have declined compared with the earlier period. For these reasons it was agreed to use only the quarter 1 survey in the assessment for the time being. The current assessment model (B-ADAPT) was considered to be too responsive to the noise levels in the surveys in recent years to form the basis for providing advice to a ...