Advice and Scenarios Database



Whiting (Merlangius merlangus) in Subarea 4 and Division 7.d (North Sea and eastern English Channel)
StockCode
whg.27.47d
Assessment Year
2020
Stock Category
1
Purpose
Advice
Published
Stock Assessment Key
13525
Link to Advice Sheet
https://doi.org/10.17895/ices.advice.5935






Catch scenarios


Basis
Total catch
Total projected landings*
Total projected discards**
Total IBC**
HCF catch 4+7.d
Total F (ages 2–6)+
F (projected landings. ages 2–6)
F (projected discards. ages 2–6)
F (IBC. ages 2–6)++
SSB
% SSB change ^
% advice change ^^
2021 2021 2021 2021 2021 2021 2021 2021 2021 2022 2022 2022
(t) (t) (t) (t) (t) (ratio) (ratio) (ratio) (ratio) (t) (%) (%)
ICES Basis Advice
MSY approach: F = FMSY 26304 14487 9584 2233 24071 0.172 0.111 0.045 0.0156 185094 2.7 19.1
Other scenarios
F = MAP## FMSY upper# 26304 14487 9584 2233 24071 0.172 0.111 0.045 0.0156 185094 2.7 19.1
F = MAP## FMSY lower 24279 13275 8758 2246 22033 0.158 0.101 0.041 0.0156 186532 3.5 9.9
F2021 = 0 (IBC only) 2376 0 0 2376 0 0.0156 0 0 0.0156 202269 12.3 -89
F2021 = F2020 31512 17603 11707 2202 29310 0.21 0.137 0.056 0.0156 181394 0.69 43
Rollover TAC 23154 12600 8301 2252 20902 0.15 0.096 0.039 0.0156 187333 4 4.9
15% TAC decrease (27.4 only) 20038 10735 7031 2271 17767 0.129 0.081 0.033 0.0156 189547 5.2 -9.3
15% TAC increase (27.4 only) 26271 14466 9572 2234 24037 0.172 0.111 0.045 0.0156 185119 2.8 19
0.75 × F2020+++ 24573 13451 8878 2244 22329 0.16 0.103 0.042 0.0156 186324 3.4 11.3
1.25 × F2020+++ 38498 21782 14556 2160 36338 0.26 0.171 0.069 0.0156 176432 -2.1 74
Fpa 49161 28162 18903 2096 47065 0.33 0.22 0.091 0.0156 168858 -6.3 122
Flim 67677 39240 26452 1985 65693 0.46 0.31 0.128 0.0156 155705 -13.6 210
SSB (2022) = Bpa= MSYBtrigger 52144 29946 20119 2078 50065 0.35 0.24 0.097 0.0156 166708 -7.4 136
SSB (2022) = Blim 117801 69230 46888 1684 116118 0.8 0.56 0.23 0.0156 119970 -33 430




Symbol Footnotes
# For this stock. FMSY upper = FMSY.
## EU multiannual plan (MAP) for the North Sea (EU. 2018).
* Marketable landings.
** The split of catch between landings. discards. and industrial bycatch (IBC) in 2021 was done using partial age-dependent fishing mortalities as a forecasting input. Partial Fs were calculated based on total F-at-age and the numbers-at-age per catch category as estimated in the assessment (average exploitation pattern of the three most recent years).
^ SSB 2022 relative to SSB 2021.
^^ Total catch 2021 relative to the advice value 2020 (22 082 tonnes).
+ Total F is calculated as the sum of partial fishing mortalities.
++ F (IBC) is assumed to be constant in all scenarios at status quo value.
+++ Multiplier only applied to F (discards) and F (landings). with F (IBC) constant.