The ICES has released its advice on 2021 fishing opportunities for Cod in division 7.e-k
The International Council of the Seas (ICES) has released its advice on fishing opportunities for Cod (Gadus morhua) in division 7.e-k (western English Channel and southern Celtic Seas) for 2021.
ICES advises that when the MSY approach and precautionary considerations are applied, there should be zero catch in 2021.
Spawning-stock biomass (SSB) has been fluctuating around MSY Btrigger since 2004, except from 2011 to 2013, and has been below Blim since 2017. Fishing mortality (F) has been above FMSY for the entire time-series, and above Flim in recent years. Recruitment has been highly variable over time. Recent recruitment has been low with the exception of the 2013 year class, which was above average.
ICES assesses that fishing pressure on the stock is above FMSY, Fpa, and Flim, and that the spawning-stock size is below MSY Btrigger, Bpa, and Blim.
Quantity of the Assessment
The stock was benchmarked in 2020 (ICES, 2020a). The model was changed to a stochastic state-space assessment model (SAM). Maturity and natural mortality information was updated, discards were included in the assessment, catch (landings and discards) time-series were reviewed and updated from 2004 to 2018, commercial tuning series were reviewed and included as biomass index, and survey indices were updated to a single modelled time-series using a vector-autoregressive spatio-temporal model (VAST). The F-pattern shows less variability across the time-series and higher estimates in most recent years than the previous assessment. Fishing mortality is observed to be sensitive to the addition of an extra year of data.
Issues relevant for the advice
ICES provides zero-catch advice for this stock in 2021, based on precautionary considerations, because the forecast is very sensitive to the assumptions on catch in 2020 and on the recruitment for 2020 and 2021. The stock is estimated to be well below Blim in 2020. Intermediate year assumptions based on status quo F or F scaled were found to produce unrealistically high catches compared to the TAC. At the time when the advice was produced (early November 2020), reported landings were about 740 tonnes of the 805 tonnes TAC. It was therefore assumed that the catches in 2020 would be the sum of landings of 805 tonnes and average discards over the last three years (250 tonnes), i.e. 1055 tonnes. This assumption resulted in a very low F value (0.477) for 2020 compared to the observed time-series and a close to 60% reduction in F from the average of the previous three years. In the ICES advice framework, this would result in advised catches of between 328 tonnes (at FMSY lower × SSB2021/MSY Btrigger) and 544 tonnes (at FMSY × SSB2021/MSY Btrigger) as the median SSB would be above Blim by 2022. The assumed recruitment in 2020 and 2021 used in the forecast would constitute a significant part of the projected catch in 2021 (39%), and a catch of 544 tonnes in 2021 would have a 26% probability that the stock is below Blim by 2022. Given the uncertainties in the forecast and that the probability of SSB being less than Blim in 2022 is greater than 5%, ICES thus provides advice for zero catch based on precautionary considerations.
Landings are adjusted to include those reported from rectangles 33E2 and 33E3 of Division 7.a, as they are considered part of this stock. This amounts to an average of 18.1% of Division 7.a landings being reallocated over the past five years and accounts for 1.48% of the official landings in divisions 7.e–k over the past five years. This should be taken into consideration when setting TACs for the two management areas (divisions 7.a and 7.e–k), as a portion of the catch taken under the Division 7.a TAC is considered to be part of the divisions 7.e–k stock. Mixed-fisheries considerations Mixed-fisheries advice will be provided in the Celtic Seas fisheries overview later in the year.
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