SUMMARY

SUMMARY

IDENTIFICATION

SCIENTIFIC NAME(s)

Nephrops norvegicus

SPECIES NAME(s)

Norway lobster, nephrops

There has been a particular focus on defining the parameters of importance for assessment and management, such as growth and maturation size as well as size frequencies at different depths and sediment types.  There are variations in the biological parameters of Nephrops from different grounds in the North Atlantic East and in the Mediterranean, which have received a lot of attention over the years (e.g.;Farmer, 1975; ICES, 2004b, 2006; Ulmestrand and Eggert, 2001).

Differences in N. norvegicus population demographic structure among geographical sectors, as well as in total mortality, appear to be highly related to different exploitation levels. Abelló et al., 2002

Low levels of differentiation were found between Norway lobster populations and there were no signs of an Atlantic–Mediterranean divide or of an isolation-by-distance scheme of differentiation. (Stamatis et al, 2004).

 Stocks are assessed at a Funtional Unit (FU) level. Each FU correspond to a specific habitat area. However, this units are managed at ICES Division level.

Thus, Nephrops management areas fall within the TAC regime of the European CFP, although allocated TACs do not coincide totally with the Functional Units.

Currently, there are no management plans applicable to the species.


ANALYSIS

Strengths

The assessment process was benchmarked in 2009, and is based on an underwater TV (UWTV) survey which is considered to be very precise. Fishers’ compliance with set TACs (entire Subarea VII) is strong. Current abundance levels are well above the MSY Btrigger.

Weaknesses

Despite ICES’ advice that management should be at the functional unit (FU) level, TACs are still set globally for Subarea VII. No specific management objectives are known for the stock. There is some by-catch of other species, such as plaice, whiting and cod.

Options

Develop a precautionary management plan for the fishery, with appropriate reference points. Management of Nephrops should be implemented at the Functional Unit level. Improve selectivity of this fishery, as recommended by ICES.

FISHSOURCE SCORES

Management Quality:

Management Strategy:

< 6

Managers Compliance:

NOT YET SCORED

Fishers Compliance:

NOT YET SCORED

Stock Health:

Current
Health:

NOT YET SCORED

Future Health:

NOT YET SCORED


RECOMMENDATIONS

RETAILERS & SUPPLY CHAIN
  • Start a fishery improvement project (FIP) to address the lack of publicly available information on this fishery. For advice on starting a FIP, see SFP's Seafood Industry Guide to FIPs and other resources at https://www.sustainablefish.org/Programs/Professional-Guidance/FIP-Toolkit-Resources
  • Encourage scientists to share their studies/publications with FishSource by commenting on the profile and uploading a hyperlink to the document.
  • Work with the government and scientists on the collection of data and make them accessible online.

FIPS

No related FIPs

CERTIFICATIONS

No related MSC fisheries

Fisheries

Within FishSource, the term "fishery" is used to indicate each unique combination of a flag country with a fishing gear, operating within a particular management unit, upon a resource. That resource may have a known biological stock structure and/or may be assessed at another level for practical or jurisdictional reasons. A fishery is the finest scale of resolution captured in FishSource profiles, as it is generally the scale at which sustainability can most fairly and practically be evaluated.

ASSESSMENT UNIT MANAGEMENT UNIT FLAG COUNTRY FISHING GEAR
Irish Sea West European Union, Division 7a Ireland Twin bottom otter trawls
United Kingdom Bottom trawls
Pots

Analysis

OVERVIEW

Strengths

The assessment process was benchmarked in 2009, and is based on an underwater TV (UWTV) survey which is considered to be very precise. Fishers’ compliance with set TACs (entire Subarea VII) is strong. Current abundance levels are well above the MSY Btrigger.

Weaknesses

Despite ICES’ advice that management should be at the functional unit (FU) level, TACs are still set globally for Subarea VII. No specific management objectives are known for the stock. There is some by-catch of other species, such as plaice, whiting and cod.

Options

Develop a precautionary management plan for the fishery, with appropriate reference points. Management of Nephrops should be implemented at the Functional Unit level. Improve selectivity of this fishery, as recommended by ICES.

RECOMMENDATIONS

Last updated on 31 December 2018

Recommendations to Retailers & Supply Chain
  • Start a fishery improvement project (FIP) to address the lack of publicly available information on this fishery. For advice on starting a FIP, see SFP's Seafood Industry Guide to FIPs and other resources at https://www.sustainablefish.org/Programs/Professional-Guidance/FIP-Toolkit-Resources
  • Encourage scientists to share their studies/publications with FishSource by commenting on the profile and uploading a hyperlink to the document.
  • Work with the government and scientists on the collection of data and make them accessible online.

1.STOCK STATUS

STOCK ASSESSMENT

The assessment is based on an UWTV (Underwater TV) survey and has been conducted annually since 2003. The survey is thought to be precise but some uncertainty is present in the estimation of bias. Discarding rates and mean weight in landings are other sources of uncertainty in the calculation of catch options. Indicators from commercial catches (size structure of catches, sex ratio and landings per unit effort), are also taken into consideration. Data and sampling quality are considered to be good (ICES, 2012).

SCIENTIFIC ADVICE

ICES advises under the MSY framework that landings in FU 15 should not exceed 9,300 tons in 2013, based on maintaining a harvest ratio of less than 17.1% (= FMSY proxy) (ICES, 2012).

To protect the stock in this functional unit, management for Nephrops in Subarea VII should be at the functional unit (FU) rather than the entire Subarea VII level. Selectivity of this fishery should also be improved to reduce bycatches of cod, whiting and undersized plaice (ICES, 2012).

Reference Points

Under the new ICES MSY framework, exploitation rates likely to provide long-term yield (and low probability of overfishing) have been examined and proposed as FMSY proxies according to determining factors affecting the biology of the stock and the nature of the fishery. For this stock, ICES concluded that a combined sex Fmax, representing a harvest ratio of 17.1%, was a suitable FMSY proxy, although it is preliminary and may be modified in future assessments. A preliminary MSY B trigger of 3 billion individuals (based on minimum abundance observed) has also been estimated, but no precautionary reference points have been defined for Nephrops (ICES, 2012).

CURRENT STATUS

Abundance data from the UWTV surveys indicates that the stock is stable and above MSY Btrigger. The size structure of catches has also remained stable over the fishery’s history. The harvest rate has fluctuated around its MSY reference point FMSY and was estimated to be just above it in 2011. Strong recruitment is ensured by the geography of the functional unit, which retains larvae (ICES, 2012).

Trends

The UWTV survey shows a generally stable trend in abundance over the past nine years, and current levels are above MSY Btrigger. Landings showed a rapid increase from the late 1940s to the early 1980s, and since then annual landings have been sustained at around 9,000 tons. Recent harvest rates have fluctuated around FMSY (ICES, 2012).

2.MANAGEMENT QUALITY

MANAGEMENT

No specific management objectives are known for this stock. Currently ICES provides advice for Nephrops stocks by functional units, whilst management (both in terms of TACs and effort) is conducted at the entire Subarea VII level. This approach (both in terms of TACs and effort) does not provide adequate safeguards to ensure that local effort is sufficiently limited to avoid depletion of resources in separate Functional Units. Catches are allowed to be taken anywhere in the ICES Division and this could imply inappropriate harvest rates from some parts (ICES, 2012). A minimum landing size of 20 mm carapace length is in place (ICES, 2012).

The Set (Agreed) TACs have exceeded advised TACs since 2005. The sum of Advised TACs for 2012 was exceeded by the set TAC (21,759 tons) by 38% (ICES, 2012).

Recovery Plans

Not applicable.

COMPLIANCE

Overall, total landings in ICES Subarea VII have historically been below the set TACs for the area. Total landings for the whole ICES subarea VII reached 16,100 tons in 2011, 26% below the agreed TAC for that year (21,759 tons). At the fishing unit level, however, landings in FU15 have been above the advised catch for that fishing area. Compliance with the minimum landings size is strong however (ICES, 2012).

Landings by some fleets prior to 2007 are thought to have been under reported. Since 2007, the implementation of ‘sales notes’ and the ‘Buyers and Sellers’ legislation, coupled with the increased TACs, is thought to have improved the reliability of reported landings (ICES, 2012).

3.ENVIRONMENT AND BIODIVERSITY

BYCATCH
ETP Species

There is no specific information on the impact of this fishery on Protected, Endangered and Threatened species. In other geographical areas, trawling for Nephrops may interact with vulnerable species such as rays and skates, whereas interactions with marine mammals are random and very rare, and no interactions have been recorded with sea turtles (Moody Marine Ltd., 2010).

Other Species

The Nephrops trawl fishery takes bycatches of other species, especially plaice but also juvenile whiting, haddock and cod. Around 45% of the Irish fleet is already using separator trawls and Swedish grids to reduce bycatch, but selectivity should be improved at the whole fishery level to reduce bycatches (ICES, 2012).

Recovery measures to protect cod include closed areas and effort limitations.

HABITAT

Nephrops are limited to a muddy habitat. The high mud content and soft nature of Nephrops grounds means that trawling readily marks the seabed, trawl marks remaining visible for some time. Despite the high intensity of fishing (some areas are impacted >7 times/year) burrowing fauna can be seen re-emerging from freshly trawled grounds, implying that there is some resilience to trawling (ICES, 2006).

Marine Reserves

In order to promote recovery of Irish cod stocks, the western Irish cod spawning grounds are closed to fishing between mid-February and end of April since 2000, with a later extension to the eastern Irish Sea (ICES, 2011b).

FishSource Scores

MANAGEMENT QUALITY

As calculated for 2012 data.

The score is < 6.

According to ICES, the management system is not precautionary enough to avoid potential local depletion of the stocks in separate functional units (ICES, 2012).

STOCK HEALTH:

To see data for biomass, please view this site on a desktop.
To see data for catch and tac, please view this site on a desktop.
To see data for fishing mortality, please view this site on a desktop.
No data available for recruitment
No data available for recruitment
To see data for management quality, please view this site on a desktop.
No data available for stock status
No data available for stock status

Download Source Data

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Fishery Improvement Projects (FIPs)

No related FIPs

Certifications

Marine Stewardship Council (MSC)

No related MSC certifications

Sources

Credits

ICES, 2011a. Report of the ICES Advisory Committee, Book 5: The Celtic Sea 5.4.34 Ecoregion: Celtic Sea. Stock: Nephrops in Subarea VII. Advice summary for 2012, 50 pp. http://www.ices.dk/committe/acom/comwork/report/2011/2011/Nep-VII.pdf

ICES, 2011b. Report of the Working Group for Celtic Seas Ecoregion (WGCSE): Chapter 6.5 Irish Sea West, FU15, 11–19 May 2011, ICES Headquarters, Copenhagen (ICES CM 2011/ACOM:12). pp. 497-523 pp.http://www.ices.dk/reports/ACOM/2011/WGCSE/06.5_Nephrops%20VIIa%20FU15.pdf

ICES, 2012. Report of the ICES Advisory Committee, Book 5: The Celtic Sea 5.4.34 Ecoregion: Celtic Sea. Stock: Nephrops in Subarea VII.http://www.ices.dk/committe/acom/comwork/report/2012/2012/Nep-VII.pdf

ICES. 2008. 5.4.34 Nephrops in Subarea VII. ICES Advice 2008, Book 5 http://www.ices.dk/committe/acom/comwork/report/2008/2008/Nep-VII.pdf

ICES. 2009. 5.4.34 Nephrops in Subarea VII. ICES Advice 2009, Book 5 http://www.ices.dk/committe/acom/comwork/report/2009/2009/Nep-VII.pdf

Moody Marine Ltd., 2010. Public Comment Draft Report for the SFSAG North Sea Nephrops Trawl Fishery. Moody Marine Ltd. / Marine Stewardship Council. May 2010. 166 pp. http://www.msc.org/track-a-fishery/in-assessment/north-east-atlantic/SFSAG-north-sea-nephrops/assessment-downloads-1/13.05.2010-sfsag-north-sea-nephrops-draft-report.pdf

References

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