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Blue Ling - Iceland and Reykjanes Ridge, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Blue Ling - Iceland and Reykjanes Ridge, 2008
Fact Sheet Citation  
Blue ling in Subdivisions Va and XIV (Iceland and Reykjanes Ridge)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
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Species:
FAO Names: en - Blue ling, fr - Lingue bleue, es - Maruca azul, ru - Мольва голубая (=биркеланга)
Geographic extent of Blue Ling - Iceland and Reykjanes Ridge
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Sub-Regional
 
 
Habitat and Biology
Depth zone: Slope (200 m - 1000 m).   Vertical distribution: Demersal/Benthic.  

Geographical Distribution
Jurisdictional distribution: National

Water Area Overview
Spatial Scale: Sub-Regional

Geo References
Resource Structure
Considered a single stock: Yes
Assessment
 
Assessment Model
Methodology

Scientific basis

The cpue series that is used as the basis for advice is derived from trips where blue ling accounts for more than 10% of the total catch (Figure 9.4.11.1.1).

Two trawl surveys are available (Figure 9.4.11.1.3). The spring survey does not cover the full depth range of blue ling and is considered inappropriate. The autumn survey does cover the full depth range, but the time-series is too short to contain a useful signal and available information indicated stability in recent years.

Landings dataseries have been extended back in time to include data not previously presented (Figure 9.4.11.1.2 and Table 9.4.11.1.1).

Comparison with previous assessment and advice

There are no changes to the perception of the status of blue ling in Subdivisions Va and XIV. The current advice is in line with previous advice.
Overall Assessment Results

Table 9.4.11.1.1.
Figure 9.4.11.1.1. Blue ling. Index of raw cpue (sum(yield)/sum(effort)) of blue ling from the Icelandic bottom trawl fishery based on logbooks 1991–2007. The criteria for the calculations were tows where blue ling composed at least 10% of the total catch in each haul.


Figure 9.4.11.1.2. Blue ling in Areas Va and XIV. Estimated total landings. Estimates for XIV prior to 1973 have not been compiled.


Figure 9.4.11.1.3. Blue ling. Abundance indices for blue ling in the groundfish survey in March 1985–2008 (SMB, line, shaded area) and October 2000–2007 (SMH, points, vertical lines). a) Abundance of fish smaller than 40 cm, b) Biomass of fish larger than 40 cm. The shaded area shows 1 standard error of the estimate.

Reference Point
 

In common with other deep-water stocks, Ulim has previously been proposed at 0.2* virgin biomass and Upa at 0.5* virgin biomass (ICES, 1998). In the absence of abundance indices that correspond to the start of the fishery, the reference points cannot be calculated.
Scientific Advice

Single-stock exploitation boundaries

There should be no directed fisheries for blue ling in Areas Va and XIV and measures should be implemented to minimize catches in mixed fisheries. Blue ling is susceptible to sequential depletion of spawning aggregations and closed areas to protect spawning aggregations should therefore be maintained and expanded where appropriate.
Management
 
Management Advice

Management considerations

Opportunistic fishery on spawning aggregations account for pulses in landings in the early 1980s and in 1993. Two closed areas to protect spawning aggregations in Subdivision Va have been introduced in 2003. If new spawning grounds are discovered it is important that an immediate closure is set in place. ICES has issued an answer to a request by NEAFC on spawning areas for blue ling in Section 9.3.2.7.

Blue ling is mostly taken as a bycatch in fisheries for cod, haddock, and saithe in Subdivision Va.
Biological State and Trend
Exploitation rate: Undefined
Abundance level: Undefined

Cpue of blue ling in Va and XIV has steadily declined from 1991 to 2000 and has remained at a low level since then (Figure 9.4.11.1.1).
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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