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
2018
Stock Category
1
Purpose
Advice
Published
Stock Assessment Key
10259
Link to Advice Sheet
NA - The advice link for key 10259 was not found!






Catch scenarios


Basis
Total catch
Total wanted catch*
Total unwanted catch*
Total IBC**
HC catch 4+7.d
HC catch 4***
HC catch 7.d***
Total F+
F (wanted catch)
F (unwanted catch)
F(IBC)++
SSB
% SSB change^
% TAC change (HC catch 4)^^
% Advice change^^^
2019 2019 2019 2019 2019 2019 2019 2019 2019 2019 2019 2020 2020 2020 2020
(t) (t) (t) (t) (t) (t) (t) (ratio) (ratio) (ratio) (ratio) (t) (%) (%) (%)
ICES Basis Advice
MSY approach: FMSY × SSB (2019)/MSY Btrigger 24195 13052 8036 3107 21088 17191 3897 0.17 0.097 0.05 0.022 156741 -4.7 -22 -7.6
Other scenarios
F = MAP FMSY ×SSB(2019)/MSYBtrigger# 24195 13052 8036 3107 21088 17191 3897 0.17 0.097 0.05 0.022 156741 -4.7 -22 -7.6
F = MAP FMSY lower ×SSB(2019)/MSYBtrigger# 22365 11919 7322 3124 19241 15686 3556 0.156 0.088 0.046 0.022 158024 -3.9 -29 -14.6
F2019 = 0(IBC only) 3298 0 0 3298 0 0 0 0.022 0 0 0.022 171547 4.3 -100 -87
F2019 = F2018 30592 17011 10534 3048 27545 22454 5090 0.22 0.129 0.067 0.022 152258 -7.4 1.8 16.8
Rollover TAC 30109 16712 10345 3052 27058 22057 5000 0.21 0.127 0.065 0.022 152597 -7.2 0 15
15% TAC decrease (27.4 only) 26088 14223 8776 3089 23007 18748 4250 0.184 0.107 0.055 0.022 155416 -5.5 -15 -0.39
15% TAC increase (27.4 only) 34131 19201 11915 3015 31110 25366 5750 0.25 0.147 0.076 0.022 149778 -8.9 15 30
0.75 × F2018+++ 24139 13017 8015 3108 21032 17145 3887 0.169 0.097 0.05 0.022 156780 -4.7 -22 -7.8
1.25 × F2018+++ 37146 21067 13093 2987 34159 27847 6313 0.27 0.162 0.084 0.022 147665 -10.2 26 42
Fpa 45429 26192 16326 2910 42519 34661 7857 0.33 0.2 0.105 0.022 141861 -13.8 57 73
Flim 62386 36686 22946 2753 59632 48612 11020 0.46 0.29 0.148 0.022 129978 -21 120 138
SSB (2020) = Bpa= MSYBtrigger 10023 4281 2503 3238 6784 5531 1254 0.063 0.027 0.014 0.022 166708 1.35 -75 -62
SSB (2020) = Blim 76556 45455 28478 2622 73934 60271 13663 0.57 0.36 0.185 0.022 119970 -27 173 192
Fmgt = 0.15 (EU–Norway Management Strategy) 21584 11436 7017 3131 18453 15043 3410 0.15 0.084 0.044 0.022 158571 -3.6 -32 -17.6
F = FMSY = FMSY upper## 24499 13240 8155 3104 21395 17441 3954 0.172 0.099 0.051 0.022 156528 -4.8 -21 -6.5
F = FMSY lower 22644 12092 7431 3121 19523 15915 3608 0.158 0.09 0.046 0.022 157828 -4 -28 -13.5
A: Max. 55797 0.407 137323 -16 113
B: Min. 15358 0.099 165613 0.6 -41
C: COD 17797 0.116 163874 -0.3 -32
D: SQ effort 30021 0.203 155219 -5.6 14
E: Value 30467 0.206 154905 -5.8 16
F: Range 24317 0.166 156347 -4.9 -7




Symbol Footnotes
# Proposed EU multiannual plan (MAP) for the North Sea (EU, 2016).
## For this stock, FMSY upper = FMSY.
* “Wanted” and “unwanted” catch are used to described fish that would be landed and discarded in the absence of the EU landing obligation, based on discard rate estimates for 2015–2017.
** The split of catch between wanted catch, unwanted catch, and industrial bycatch (IBC) in 2019 was done using partial age-dependent fishing mortalities as 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).
*** The human consumption (HC) catch split between Subarea 4 and Division 7.d in 2018 is the same as the proportion of HC catch between the areas in 2017: 81.5% from Subarea 4 and 18.5% from Division 7.d. This assumes that management for Division 7.d is separate from Subarea 7. Total catches are based on a combined discard rate for Subarea 4 and Division 7.d.
^ SSB 2020 relative to SSB 2019.
^^ Human consumption catch (HC catch) for Subarea 4 in 2019 relative to TAC for Subarea 4 and Division 2.a in 2018 (22 057 t).
^^^ Total catch 2019 relative to the advice value 2018 (26 191 t).
+ Total F is calculated as the sum of partial fishing mortalities.
++ F(IBC) assumed to be constant in all scenarios at status quo value.
+++ Multiplier only applied to F(UW) and F(WC), F(IBC) constant.
A. Maximum scenario: Each fleet stops fishing when its last stock share is exhausted.
B. Minimum scenario: Each fleet stops fishing when its first stock share is exhausted.
C. COD: Each fleet stops fishing when its individual cod share is exhausted.
D. SQ (status quo) effort scenario: The effort of each fleet in 2018 and 2019 is as in 2017.
E. Value scenario: The effort of each fleet is equal to the weighted average of the efforts required to catch the fleet’s quota share of each of the stocks, where the weights are the relative catch values of each stock in the fleet’s portfolio.
F. Range scenario: The potential for TAC mismatches in 2018 are minimized within the FMSY range, for the demersal fish stocks for which such a range is available (cod.27.47d20; had.27.46a20; pok.27.3a46; ple.27.420; ple.27.7d; sol.27.4; sol.27.7d; whg.27.47d).