1. K:09
Mixed fisheries forecasts – lessons learned from their initial application to North Sea fisheries.
Steven J. Holmes, Clara Ulrich
& Stuart A. Reeves

2. Limits of the single species approach
SSB F
COD F
SSB
HAD

3. Limits of the single species approach

4. Fleets & Métiers Fleet (vessel) Métier (trip) Species (catches) EFFORT
CATCHABILITY

5. ICES ADVICE Assessment Assumption Advice Cod ->2011 Fishing Mort.
Abundance
Cod 2012 F
Recruitment
Cod 2013
scenarios F values, TAC
Cod Effort/Fleet
MIXED-FISHERIES
F=qE
SCENARIOS !
Haddock Effort/Fleet
Haddock
->2011
Haddock
2012
Haddock
2013

6. Pragmatic steps required to
Aim of talk
Pragmatic steps required to
Account for all stocks of major importance in N Sea.
Allow results to be of use to managers & the management process.
Latest developments.
Pointer to future developments.

7. Moving to Mixed-Fisheries Advice
ICES WKMIXMAN 2006 : review of mixed-fisheries models. Fcube model proposed as promising method.
2006 : Trial runs in WGHMM and WGNSSK.
FP6 AFRAME (North Sea, Western Waters, Greek Waters).
ICES SGMIXMAN : further testing and development.
2009 : Putting this into practice – Advice for the North Sea based on WGNSSK 2009 single-stock advice
WKMIXFISH (Aug. 2009)
AGMIXNS (Nov 2009 with ACOM)
Ulrich et al. 2011, IJMS, 68: 1535–1547

8. TV survey
Farn Deeps
Fladen
Firth of Forth
Moray Firth
No survey
Botney Gut
Noup
Norwegian Deep
Horn’s Reef
Devil’s Hole

9. Data needed Nephrops FUs with TV survey FUs with no TV survey
Project latest biomass estimate unchanged
Use status quo catchability Catch/(Biomass*Effort)
For each scenario - calculate a ratio (R) of the yields to the ICES’ advice for the same FUs
FUs with no TV survey
Multiply the most recent recorded landings by an average of the ratios (R) values
Data needed
landings by métier by FU

10. Moving to Mixed-Fisheries Advice
ICES WKMIXMAN 2006 : review of mixed-fisheries models. Fcube model proposed as promising method.
2006 : Trial runs in WGHMM and WGNSSK.
FP6 AFRAME (North Sea, Western Waters, Greek Waters).
ICES SGMIXMAN : further testing and development.
2009 : Putting this into practice – Advice for the North Sea based on WGNSSK 2009 single-stock advice
WKMIXFISH (Aug. 2009)
AGMIXNS (Nov 2009 with ACOM)
From 2010 : WGMIXFISH (August)

11. The advice cycle
1st Jan
TACs agreed
Data
WGNSSK
MIXFISH
WGNSSK
STECF advice
ICES advice released

12. Joint WGNSSK-WGMIXFISH data call
Fleet&métier lnds&discards
Fleet&métier effort (kWdays)
WGNSSK
No.s at age
Wghts at age
Data call based on DCF classifications
Upload to
Allocation of discards to unsampled fleets within
Allocation of age distributions to unsampled fleets within
ICES InterCatch

13. WebEx’s testing allocations scheme in InterCatch on trial run data &
Final data call spec
(Dec 2011-Jan 2012)
Info from Nat. institutes
(Sept 2011)
Joint WGNSSK-WGMIXFISH
Data call
(Feb 2012)
Trial data call using min set of ‘métier tags’ consistent with phase 1
(Sept-Dec 2011)

14. Pluses (& headache) for WGNSSK
Much greater transparency in provenance and derivation of the final data set.
How much data comes from fully sampled data sets (including discards).
What was the process of assignments.
Allows for assignments between similar fleets of different nations (rather than simply across entire national fleets).
The new process of building total numbers at age landed and discarded – including ability to assign between fleets internationally – NO major evidence of discontinuity in catch data.

16. DO NOT attempt to read this

17. Additions to single species outlook tables: Mixed fishery scenarios

18. Lessons Learnt Data; never underestimate.
The amount by which data supplied to different data calls can be inconsistent.
The importance (and difficulty) of defining a data call.
The time needed to check submitted data.
Presenting results in a digestible form needs careful consideration.
It is not just a case of what you do but when you do it.
Split ‘operational’ WGs and methodological development.

19. Fmsy in 2015
COD LANDINGS

20. Fmsy in 2015
F/Fmsy
SSB/Bmsy

21. Fmsy in 2015
Comparison of scenarios, all stocks
sq_E
Ef_Mgt
F/Fmsy
F/Fmsy
SSB/Bmsy
SSB/Bmsy

22. The Future More stocks, e.g. VIId plaice and sole.
Joint N.Sea-WoS forecasts?
Saithe, anglerfish and megrim all combined VI and IV stocks.
Issue of landings representing very different ratio of catch weight and mean F.
New approaches to stocks without full analytical assessments.

23. The Future Expansion into new areas Imbed into single stock WGs
Expertise in Fcube
Consistent data (more joint data calls)
Test the waters