Report of the Working Group on Mixed Fisheries Advice for the North Sea (WGMIXFISH-NS), 26-30 May 2014, ICES HQ, Copenhagen, Denmark

Type Expertise
Date 2014
Language English
Ref. ICES CM 2014/ACOM:22
Other localization
Author(s) ICES
Contributor(s) Vermard YouenORCID
Sponsor ICES
Publisher ICES
Abstract The ICES Working Group on Mixed Fisheries Advice for the North Sea [WGMIXFISH-NS] (Chair: Paul Dolder (UK)) met at ICES HQ, 26—30 May 2014 to apply mixed fish-eries forecasts to the draft North Sea single species advice formed by WGNSSK 2014.
The meeting has produced a North Sea Mixed Fisheries Advice sheet and included lines showing mixed fisheries scenario outcomes in the single species advice sheets (for those stocks considered) for consideration by the ACOM advice drafting group. It did not consider ToR c (application of the FCube methodology to the West of Scotland fish-eries) due to a lack of available expertise in this geographic area or ToR d (application to the Iberian waters) which is deferred to the October meeting when relevant experts will be available.
The North Sea mixed fisheries runs followed the approach used by ICES; management plan where it exists and MSY approach otherwise. The species considered here as part of the demersal mixed fisheries of the North Sea are cod, haddock, whiting, saithe, plaice, sole, and Nephrops norvegicus, as well as plaice VIId and soleVIId. The North Sea (ICES area IV) turbot stock was also added to the full scenario calculations this year. All of these are now subject to multi-annual management plans apart from turbot, plaiceVIId, soleVIId and Nephrops. Following the decision to extend the definition of the haddock stock to include the west of Scotland (ICES Subarea VIa), ICES considered the north sea haddock management plan to no longer apply, and the MIXFISH fore-casts similarly follow MSY approach advice for this stock. Five scenarios were consid-ered.
1 ) max: The underlying assumption was that fishing stops when all quota spe-cies are fully utilized with respect to the upper limit corresponding to single-stock exploitation boundary.
2 ) min: The underlying assumption was that fishing stops when the catch for the first quota species meets the upper limit corresponding to single-stock exploitation boundary.
3 ) cod: The underlying assumption was that all fleets set their effort at the level corresponding to their cod quota share, regardless of other stocks.
4 ) sq_E: The effort was set as equal to the effort in the most recently recorded year for which there are landings and discard data.
5 ) Ef_Mgt: The effort in métiers that used gear controlled by the EU effort man-agement regime had effort adjusted according to the regime.
The max and min scenarios were included to bracket the space of potential catch and SSB outcomes but for most fleets are considered unrealistic scenarios. Of the remaining scenarios none was picked as a preferred scenario. Effort limits under the EU effort management regime were left unchanged in 2013 and 2014 and the WG considered the relationship between F and effort changes under the long term management phase of the cod recovery plan open to interpretation but still included the scenario, having made its own interpretation of the control rule.
Exploratory analyses were undertaken to allow consideration of the level of cod avoid-ance required to be consistent with the single-stock exploitation boundaries for the cod stock in the absence of further adjustments to fishing effort ceilings. These are included as a ‘cod catchability reduction’ scenario.
The most limiting stocks (i.e. the stocks which are the first quota reached for most fleets) in the North Sea demersal mixed fisheries in 2015 were cod and Nephrops FU6 (Farn Deeps). The least limiting stocks (i.e. the stocks which were the last quotas to be fulfilled) were haddock and Nephrops FU7 (Fladen grounds). The ‘cod catchability re-duction’ analysis indicates cod avoidance at the level of an additional 40—50% of 2013 level would be required in order to meet the cod single-stock target which the current level of fishing effort.
The impact of mixed fisheries scenarios on seven further stocks; brill, dab, flounder, hake, lemon sole, red mullet and witch were considered without their incorporation into the mixed fisheries projections. All TACs of these stocks except the North Sea com-ponent of the hake TAC were predicted to be underutilized under assumption of status quo effort, while hake was predicted to be subject to over-quota catches under all sce-narios, including ‘min’.
In 2014 data for this WG was requested as part of a joint WGNSSK-WGMIXFISH-WGNEW data call which allows a greater consistency between catch totals supplied to WGMIXFISH, WGNSSK and WGNEW and additional stocks to be included in the mixed fishery forecasts. It is expected that further stocks will be able to be considered in the mixed fisheries projections as assessments become available.
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ICES (2014). Report of the Working Group on Mixed Fisheries Advice for the North Sea (WGMIXFISH-NS), 26-30 May 2014, ICES HQ, Copenhagen, Denmark. ICES, Ref. ICES CM 2014/ACOM:22, 95p.