Advice and Scenarios Database



Witch (Glyptocephalus cynoglossus) in Subarea 4 and divisions 3.a and 7.d (North Sea, Skagerrak and Kattegat, eastern English Channel)
StockCode
wit.27.3a47d
Assessment Year
2019
Stock Category
1
Purpose
Advice
Published
Stock Assessment Key
12955
Link to Advice Sheet
https://doi.org/10.17895/ices.advice.4879






Catch scenarios


Basis
Total catch
Wanted catch*
Unwanted catch*
Ftotal ages 4–8
Ftotal ages 4–8
SSB
SSB
% SSB change **
% Advice change ***
2020 2020 2020 2020 2021 2020 2021 2021 2021
(t) (t) (t) (ratio) (ratio) (t) (t) (%) (%)
ICES Basis Advice
Precautionary approach: Fpa 1651 1608 43 0.2 0.2 4101 3622 -11.7 -31
Other scenarios
MSY approach: FMSY 1301 1266 35 0.154 0.154 4206 3915 -6.9 -46
FMSY-upper[1] 1726 1680 47 0.21 0.21 4078 3559 -12.7 -28
FMSY-lower 938 913 25 0.108 0.108 4315 4229 -2 -61
F = 0 0 0 0 0 0 4578 5027 9.8 -100
Fpa 1651 1608 43 0.2 0.2 4101 3622 -11.7 -31
Flim 2350 2286 64 0.3 0.3 3880 3061 -21 -1.66
Fsq 1924 1866 59 0.24 0.24 4011 3393 -15.4 -19.5
SSB (2021) = Blim 2339 2275 64 0.3 0.3 3883 3069 -21 -2.1
SSB (2021) = Bpa 312 304 7 0.035 0.035 4492 4745 5.6 -87
SSB (2021) = MSYBtrigger 312 304 7 0.035 0.035 4492 4745 5.6 -87
Roll-over advice 2390 2326 64 0.31 0.31 3866 2846 -26 0




Symbol Footnotes
* “Wanted” and “unwanted” catch are used to describe fish that would be landed and discarded in the absence of the EU landing obligation, based on average discard rate estimates for 2016–2018.
** SSB in 2021 relative to SSB in 2020.
*** Total catch in 2020 relative to advice value 2019 (2390 tonnes).