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
2017
Stock Category
1
Purpose
Advice
Published
Stock Assessment Key
9245
Link to Advice Sheet
NA - The advice link for key 9245 was not found!






Catch scenarios


Basis
Total catch
Total wanted catch 4+7.d*
Total unwanted catch*
Total IBC**
Wanted catch 4***
Wanted catch 7.d***
Total F
F (wanted catch)
F (unwanted catch)
F(IBC)
SSB
% SSB change^
% TAC change (wanted catch) ^^
2018 2018 2018 2018 2018 2018 2018 2018 2018 2018 2019 2019 2019
(t) (t) (t) (t) (t) (t) (ratio) (ratio) (ratio) (ratio) (t) (%) (%)
ICES Basis Advice
MSY approach: FMSY 26191 13799 8546 3846 11040 2759 0.15 0.088 0.04 0.023 293339 -18.2 -31
Other scenarios
F = 0 (IBC only) 4008 0 0 4008 0 0 0.023 0 0 0.023 311439 -13.2 -100
F = F2017 42196 23731 14737 3728 18986 4745 0.244 0.152 0.069 0.023 280305 -21.9 19
Rollover TAC 36266 20002 12492 3771 16003 3999 0.213 0.131 0.06 0.023 285191 -20.5 0
15% TAC decrease (27.4 only) 31395 17002 10585 3807 13603 3400 0.182 0.11 0.05 0.023 289132 -19.4 -15
15% TAC increase (27.4 only) 41137 23003 14399 3735 18403 4599 0.243 0.151 0.069 0.023 281250 -21.6 15
0.75 × F2017 32372 17605 10967 3800 14085 3520 0.188 0.114 0.052 0.023 288339 -19.6 -12
1.25 × F2017 50190 28578 17944 3669 22864 5714 0.299 0.19 0.087 0.023 273928 -23.7 43
Fpa 47142 26701 16750 3691 21362 5339 0.28 0.177 0.081 0.023 276393 -23 33
Flim 64869 37618 23692 3560 30096 7522 0.39 0.252 0.115 0.023 262055 -27 88
SSB (2019) = Bpa= MSYBtrigger 89780 52958 33446 3376 42369 10589 0.545 0.359 0.163 0.023 241837 -32.6 165
SSB (2019) = Blim 175057 105472 66838 2747 84383 21089 1.074 0.722 0.329 0.023 172741 -51.8 427
Fmgt = 0.15 (EU–Norway Manage-ment Plan) 31395 17002 10585 3807 13603 3400 0.182 0.11 0.05 0.023 289132 -19.4 -15
A: Max. 134306 0.87 274853 -22
B: Min. 15153 0.08 367550 4
C: HAD 25676 0.13 363256 3
D: POK 46139 0.26 335921 -5
E: SQ effort 37594 0.2 349038 -1
F: Value 33833 0.18 352637 0




Symbol Footnotes
* “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 2014–2016.
** The split of catch between wanted catch, unwanted catch, and industrial bycatch (IBC) in 2018 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 wanted catch split between Subarea 4 and Division 7.d in 2018 is the same as the proportion of landings between the areas in 2016: 80% from Subarea 4 and 20% 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 2019 relative to SSB 2018.
^^ Human consumption (HC; wanted catch) for Subarea 4 in 2018 relative to TAC for Subarea 4 and Division 2.a in 2017 (16 003 t).
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. HAD: Each fleet stops fishing when its individual haddock share is exhausted.
D. POK: Each fleet stops fishing when its individual saithe share is exhauste
E. SQ (status quo) effort scenario: The effort of each fleet in 2017 and 2018 is as in 2016.
F. 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.