Habitat and Biology
Depth zone: Shelf (50 m - 200 m). Vertical distribution: Demersal/Benthic.
The North Sea haddock stock exhibits sporadic high recruitment, leading to dominant year classes in the fishery. These large year classes often grow more slowly than less abundant year classes, possibly due to density-dependent effects. Recruitment appears poorly determined by either spawning-stock biomass or egg production. Haddock primarily prey on benthic and epibenthic invertebrates, sandeels, and herring eggs. Haddock are an important prey species, mainly for saithe and other large gadoids.
Environmental influence on the stock
Haddock growth may be linked to water temperature. Warmer waters may lead to faster growth in early life stages, but also to faster maturation and a lower maximum size. There are indications that haddock recruitment success is determined, in part, by the available area of suitable substrate at settlement time.
Jurisdictional distribution: Shared between nations
Considered a single stock: Yes
Haddock are primarily caught by demersal trawlers (single, twin, and pair), and (to a lesser extent) by seiners. Haddock is a specific target for some fleets, but is also caught as part of a mixed fishery catching cod, whiting, and Nephrops. The minimum permitted mesh size for targeted fisheries was increased to 120 mm in 2002. Estimates of haddock bycatch in the industrial fishery are low, based on the assumption that bycatch rates remain as observed in recent years, when the industrial fisheries were at a low level.
|Catch by fleet
||Total catch (2011) was 34.4 kt, where 75% were landings (86% demersal trawl and seine >100 mm, 11% Nephrops trawl 70–99 mm, and 3% others), 25% discards, and 0% industrial bycatch.
Effects of the fisheries on the ecosystem
Trawling impacts the benthos, as summarized in the North Sea ecosystem overview. Trawl gear are also relatively non-selective in terms of species caught, and trawl fisheries have a bycatch of non-commercial species that are important components of the North Sea ecosystem.
ICES advises on the basis of the EU–Norway management plan that landings in 2013 should be no more than 47 811 t.
Overall Assessment Results
Assessment ModelQuality consideration
The assessment and forecast are largely influenced by the 2005 and 2009 year classes. The overall reporting (in particular through the fully documented fisheries (FDF) programme) of catch data provided to ICES has improved in 2012. International landings and discard rate estimates were provided and raised according to the Data Collection Framework (DCF) métier categories.Scientific basis
||Age-based analytical assessment (XSA).
||Three survey indices: IBTS Q1, ScoGFS Q3, EngGFS Q3.
|Discards and bycatch
||Discards and industrial bycatch are included in the assessment.
||Benchmarked in early 2011 (WKBENCH 2011).
|Working group report
Management unit: YesManagement plans
A management plan was agreed by EU and Norway in 2008 (see Annex 6.4.3). ICES has evaluated the plan and concludes that it can be accepted as precautionary.
Biological State and Trend
Source of information
The above excerpts are from the first two pages of the ICES advice, the supporting information to this advice can be read in full at the following reference:
ICES. . Haddock in Subarea IV (North Sea) and Division IIIa West (Skagerrak) Report of the ICES Advisory Committee, 2012. ICES Advice, WGNSSK, 2012. http://www.ices.dk/committe/acom/comwork/report/2012/2012/had-34.pdf