Report of the Benchmark Workshop on Norway Pout (Trisopterus esmarkii) in Subarea 4 and Division 3.a (North Sea, Skagerrak and Kattegat) (WKPOUT)

The Benchmark Workshop on Norway Pout (WKPout), chaired by External Chair Jerry Ault, USA, and ICES Chair José De Oliveira, UK, met at ICES HQ, Copenhagen on 23–25 August 2016. There were 13 participants, including three external reviewers (two from USA, one from France), Danish, Norwegian and UK scientists, and Danish Industry representatives. The benchmark followed a data evaluation workshop in May 2016 during which input data for the assessment were agreed. The main focus of the benchmark was to agree a new assessment methodology, seasonal SAM (SESAM), for Norway Pout. In addition, reference points and forecasting methodology were discussed. A number of variants of the SESAM model were investigated and compared to the previous assessment model, SXSA. These variants included the use (or not) of commer-cial cpue data, omission of the earliest years of data from the assessment, alternative settings for the detection threshold used to handle zero-valued data, and omitting the years of fishery closure when estimating the random walk variance on fishing mortality. The final SESAM model excludes commercial cpue data, omits 1983 data from the assessment and omits the years of fishery closure from the random walk variance calculation. B_lim is set equal to B_loss based on quarter 4 SSB values to align with the new fishing season (1st November to 31st October). The short-term forecast is stochastic, which allows the probability of SSB being below B_lim to be evaluated immediately following the fishing season.