The ICES has released its advice on fishing opportunities, catch, and effort Celtic Seas, Greater North Sea, and Oceanic Northeast Atlantic ecoregions for Whiting (Merlangius merlangus) in divisions 7.b–c and 7.e–k (southern Celtic Seas and western English Channel) for 2021.
ICES advises that when the EU multiannual plan (MAP) for Western Waters and adjacent waters is applied, catches in 2021 that correspond to the F ranges in the MAP are between 4458 tonnes and 5261 tonnes.
The spawning-stock biomass (SSB) has decreased since 2010 and is estimated to have been below MSY Btrigger since 2017 and below Blim since 2018. Fishing mortality (F) has generally fluctuated above FMSY throughout the time-series and was below FMSY in 2019. Recruitment has been relatively low since 2010, with the exception of 2013.
Quality of the assessment
The stock assessment was benchmarked in 2020 (ICES, 2020a). The model has been changed to a stochastic state-space assessment model (SAM). Maturity and natural mortality information were updated, catch (landings and discards) timeseries were reviewed and updated from 2003 to 2018, and survey indices updated to a single-modelled time-series, using the vector-autoregressive spatio-temporal model (VAST). These changes resulted in revised estimates of SSB, F, and reference points.
Issues relevant for the advice
The assessment and the advice are for divisions 7.b–c and 7.e–k, including reallocations from rectangles 33E2 and 33E3 in Division 7.a. There has been a significant amount of discarding historically, but this is now decreasing. Whiting in divisions 7.b–c and 7.e–k is fished under a common TAC with whiting in Division 7.d. By mixing the biological and TAC areas for different whiting stocks, it will be difficult to achieve the objective of fishing at maximum sustainable yield (MSY) for both stock areas. Hence, ICES recommends that the TAC area corresponds to the assessment area. Mixed-fisheries considerations Whiting in divisions 7.b–c and 7.e–k is caught as part of a mixed fishery with haddock and cod. Mixed-fisheries advice will be provided in the Celtic Seas fisheries overview later in the year.
The full report can be read here.