Last updated on 4 November 2016

SUMMARY

SUMMARY

IDENTIFICATION

SCIENTIFIC NAME(s)

Mytilus edulis

SPECIES NAME(s)

Blue mussel

COMMON NAMES

Blue shell mussel

There is no information available regarding the population structure of this species in the area.


ANALYSIS

Strengths

The Stock status is considered to be in a good condition and increasing in size. Fishing pressure is low. Compliance with regulations is deemed to be strong and managers follow scientific advice. This fishery is MSC certified since 2010.

Weaknesses

Mussel dredging impacts on the sea bottom habitats are not fully understood yet.

Options

Continue the research underway to evaluate impacts of mussel dredging on the bottom habitats structure and to develop less impacting fishing gears.

FISHSOURCE SCORES

Management Quality:

Management Strategy:

≥ 6

Managers Compliance:

≥ 8

Fishers Compliance:

≥ 8

Stock Health:

Current
Health:

≥ 8

Future Health:

≥ 8


FIPS

No related FIPs

CERTIFICATIONS

  • Vilsund Blue a/s Limjord mussel & cockle dredge:

    MSC Recertified

  • DFPO Limfjord mussel and cockle fishery:

    MSC Certified

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
Limfjord Denmark Limfjord Denmark Miscellaneous - rope grown
Towed dredges

Analysis

OVERVIEW

Strengths
Denmark Limfjord
Denmark
Towed dredges

The Stock status is considered to be in a good condition and increasing in size. Fishing pressure is low. Compliance with regulations is deemed to be strong and managers follow scientific advice. This fishery is MSC certified since 2010.

Weaknesses
Denmark Limfjord
Denmark
Towed dredges

Mussel dredging impacts on the sea bottom habitats are not fully understood yet.

Options
Denmark Limfjord
Denmark
Towed dredges

Continue the research underway to evaluate impacts of mussel dredging on the bottom habitats structure and to develop less impacting fishing gears.

1.STOCK STATUS

SCIENTIFIC ADVICE
Denmark Limfjord
Denmark
Towed dredges

Scientific advice is provided by several organizations, but mainly by the Danish Technical University (DTU Aqua). Among other research related with the mussel fishery, DTU Aqua conducts regular stock assessments in order to evaluate the stock status. More recently, a permanent Mussel production Committee was created, aiming at giving advice to the Minister of Food, Agriculture and Fisheries with regards to management of mussel production (Dolmer et al., 2010).

CURRENT STATUS
Denmark Limfjord
Denmark
Towed dredges

Stock status is considered good and reported to be increasing in size (Andrews et al., 2012).

Trends

Landings have been decreasing since 2005, but more as a result of fishers’ voluntary cuts on the weekly quotas than by the stock status (Dolmer et al., 2010). The stock biomass is in an increasing trend since 2006 Andrews et al., 2012).

2.MANAGEMENT QUALITY

MANAGEMENT
Denmark Limfjord
Denmark
Towed dredges
Recovery Plans

Not applicable.

COMPLIANCE
Denmark Limfjord
Denmark
Towed dredges

Compliance with regulations is deemed to be strong. Catches are considered to be within the agreed limits (Andrews and Brand, 2011; Andrews et al., 2012).

3.ENVIRONMENT AND BIODIVERSITY

BYCATCH
ETP Species
Denmark Limfjord
Denmark
Towed dredges

Several seabird species occur in the area were mussel fishing takes place. According to recent assessments “No plausible link between mussel fishing activity and bird abundance has been identified” (Andrews and Brand, 2011).

Other Species
Denmark Limfjord
Denmark
Towed dredges

The main bycatch and discarded species within this fishery are starfish, some gastropods, ascidians, shore crabs, bivalve and, less frequently, flatfish (Dolmer et al., 2010). According to Dolmer et al. (2010), given that only 5% of the fjord area is explored annually, the bycatch levels observed are not likely to pose a significant risk to the species concerned.

HABITAT
Denmark Limfjord
Denmark
Towed dredges

Mussel dredges may alter the sea floor structure by removing hard substrate such as stones, shells and boulders. As an MSC condition, a research project has recently taken place (and remains underway) to evaluate impacts of mussel dredges on the sea floor and test new fishing methods to reduce impacts on habitat (Andrews et al., 2012).

Marine Reserves

According to Dolmer et al. (2010), only 5% of the fjord area is subject to mussel dredging each year. Besides temporally closures of some areas, approximately 50% of the entire Limfjord area is closed to mussel dredging, including all shallower areas (<3 meters depth). The mussel fishery closes in a specific area if juvenile mussels comprise more than 30% of catches (Dolmer et al., 2010).

FishSource Scores

Last updated on 27 January 2017

MANAGEMENT QUALITY

As calculated for 2011 data.

The score is ≥ 6.

The current management strategy has a series of tools that are considered effective in maintaining the stock exploitation at sustainable levels. Harvest control measures are based upon regular stock assessments. Such measures include annual quotas (or TACs) in Natura 2000 areas, weekly quotas (in place elsewhere), minimum landing sizes (4.5 cm), and spatial and temporal closures to control fishing effort (Dolmer et al., 2010; Andrews and Brand, 2011).

As calculated for 2011 data.

The score is ≥ 8.

Management measures are based on regular research such as stock assessments and scientific advice (Dolmer et al., 2010). A Mussel Management Committee was recently established, in order to create a forum between all key stakeholders and manage the fishery more effectively (Andrews and Brand, 2011).

As calculated for 2012 data.

The score is ≥ 8.

Compliance with regulations is deemed to be strong. Catches are considered to be within the agreed limits (Andrews and Brand, 2011; Andrews et al., 2012).

STOCK HEALTH:

As calculated for 2012 data.

The score is ≥ 8.

Stock status is considered good and reported to be increasing in size (Andrews et al., 2012).

As calculated for 2012 data.

The score is ≥ 8.

Stock is increasing in size and fishing pressure is considered “relatively low” (Andrews et al., 2012)

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.
No data available for fishing mortality
No data available for fishing mortality
No data available for recruitment
No data available for recruitment
To see data for management quality, please view this site on a desktop.
To see data for stock status, please view this site on a desktop.
DATA NOTES

1)* Lack of biological reference points and fishing quotas to all areas prevents the calculation of scores 1-5; qualitative scores have been attributed instead. *2)* Biomass is used as a proxy of SSB in the scores data sheet (Dolmer et al., 2010).

Download Source Data

Registered users can download the original data file for calculating the scores after logging in. If you wish, you can Register now.

Fishery Improvement Projects (FIPs)

No related FIPs

Certifications

Marine Stewardship Council (MSC)

SELECT MSC

NAME

Vilsund Blue a/s Limjord mussel & cockle dredge

STATUS

MSC Recertified on 7 January 2010

SCORES

Principle Level Scores:

Principle Score
Principle 1 – Target Species: Mussels 86.3
Principle 1 – Target Species: Cockles 84.2
Principle 2 - Ecosystem: Mussels 88.0
Principle 2 - Ecosystem: Cockels 82.7
Principle 3 – Management System 91.0

Certification Type: Bronze

Sources

Credits

Andrews, J.W. and Brand, A.R., 2011. Surveillance Report 1 for the Danish Blue Shell Mussel Fishery, Limfjord. Moody Marine Ltd. May 2011. 11 pp. http://www.msc.org/track-a-fishery/certified/north-east-atlantic/denmark-blue-shell-mussel/assessment-downloads-1/26.05.2011_Limfjord_Mussels_Surveillance_FINAL.pdf

Andrews, J.W., Brand, A.R. and Maar, M.A., 2012. Surveillance Report 2 for the Danish Blue Shell Mussel Fishery, Limfjord. Moody Marine Ltd. January 2012. 16 pp. http://www.msc.org/track-a-fishery/certified/north-east-atlantic/denmark-blue-shell-mussel/assessment-downloads-1/20120104_SR_final.pdf

Andrews, J.W., Brand, A.R., Maar, M.A. 2013. Surveillance Report 3 Danish Blue Shell Mussel Fishery, Limfjord. Intertek Moody Marine Ltd., May 2013. 29pp http://www.msc.org/track-a-fishery/fisheries-in-the-program/certified/north-east-atlantic/denmark-blue-shell-mussel/assessment-downloads-1/20130528_SR_MUS35.pdf

Brand, A.R., Maar M., Andrews, J.W., 2015. Vilsund Blue a/s Limjord Mussel and Cockle Dredge Fishery. Public Certification Report. Intertek Fisheries Certification (IFC), January 2015. 269pp http://www.msc.org/track-a-fishery/fisheries-in-the-program/certified/north-east-atlantic/vilsund-blue-a-s-limjord-mussel-and-cockle-dredge/reassessment-downloads/20150106_PCR_MUS035.PDF

Dolmer, P., Holt, T., Hough, A. and Davies, S., 2010. Public Certification Report for the Danish Blue Shell Mussel Fishery, Limfjord. Moody Marine Ltd. January 2010. 154 pp. http://www.msc.org/track-a-fishery/certified/north-east-atlantic/denmark-blue-shell-mussel/assessment-downloads-1/15.01.2010-denmark-blue-shell-mussel-pcr.pdf

References

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