1. Horse Mussel Reefs in Strangford Lough
Dai Roberts, Chris Maggs, Louise Allcock [Principal Investigators]
James Strong, Dave Smyth, Anne-Marie McMahon, Jose-Maria Fariňas Franco [Research Team]
Modiolus Restoration Research Group at Queen’s

2. Horse Mussels in Strangford Lough
Loss of Biodiversity
Over the last 100 years the rate of loss of
biodiversity in the world has accelerated
dramatically:
More than 11,000 species currently face extinction
Amazonian deforestation has increased from 30,000 km2 pa in 1975 to 600,000 km2 pa now
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Horse Mussels in Strangford Lough

3. Examples of biodiversity decline in Northern Ireland
Native oysters (Ostrea edulis): stocks in Strangford Lough collapsed 100 years ago
Freshwater pearl mussels (Margaritifera margaritifera) have declined steadily over the last 100 years and are now only found in 4 rivers
Horse mussels (Modiolus modiolus) declined in Strangford Lough in late 1980s
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Horse Mussels in Strangford Lough

4. Horse Mussels in Strangford Lough
Why should we protect biodiversity ?
How can we protect biodiversity ?
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Horse Mussels in Strangford Lough

5. Horse Mussels in Strangford Lough
Why ?
Humans have an ethical responsibility to preserve biodiversity because it:
provides ‘ecosystem services’ – ecological processes are essential to maintain life-support systems (pure air, water and soil)
maintains long-term viability of agriculture and fisheries
provides food, fibre, drinks
is a basis of new medicines
supports many local communities
has intrinsic value
We can’t ignore the first of these points and the second point is directly relevant to the current project
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Horse Mussels in Strangford Lough

6. Horse Mussels in Strangford Lough
‘ecosystem services’ provided by horse mussels – water filtration:
1 mussel filters about 1L water per hour
1000 mussels can filter about 24 tonnes
water per day
and 1 million mussels about 24,000 tonnes per day
Complex habitats like mussel reefs provide
important nursery grounds for species
caught in commercial fisheries
Mussels are important biological ’engineers’ in both freshwater and marine ecosystems. When they feed they filter vast quantities of water thereby improving water quality.
A frequently cited example is that of a population of blue mussels which were capable of filtering the entire contents of the Albert Dock in Liverpool in 2 days.
Horse mussels work in the same way; they also provide habitat for over a hundred other species and thereby serve as a nursery ground for species of commercial importance.
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Horse Mussels in Strangford Lough

7. Political Landmark 1992: signing Biodiversity Convention
How ?
Political Landmark 1992: signing Biodiversity Convention
In Europe, the biodiversity convention is implemented through the Habitats Directive which establishes a common framework across the European Union for “the maintenance of biodiversity, taking account of economic, social, cultural and regional requirements.”
At the Earth Summit in Rio de Janeiro in 1992 world leaders accepted the responsibility to look after their own countries’ wildlife, species and habitats by signing the ‘Biodiversity Convention’
Aims to protect habitats and species
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Horse Mussels in Strangford Lough

8. Horse Mussels in Strangford Lough
Modiolus clump in intact Modiolus/Chlamys biotope
The problem
Area of dead Modiolus shell – main channel, north basin.
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Horse Mussels in Strangford Lough

9. Horse Mussels in Strangford Lough
In December 2005 DARD and DOE developed the Modiolus Restoration Plan for Strangford Lough to:
protect the remaining Modiolus biogenic reefs (short term)
assess whether conditions in Strangford Lough are currently suitable for restoration (short term)
look for evidence of recovery of the reefs (medium term)
restore the Strangford Lough Modiolus reefs to ‘Favourable Conservation Status’ (long term)
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Horse Mussels in Strangford Lough

10. Horse Mussels in Strangford Lough
Queen’s Modiolus Restoration Research Group
will provide technical scientific support for the
restoration plan by:
Mapping – broad-scale, using ROV and extent diving
– detailed boundary mapping using acoustic tracking
Monitoring – using videos and sampling
condition by divers
Intervention – translocation, spat collection,
trials cultch
– aquaculture
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Horse Mussels in Strangford Lough

11. Horse Mussels in Strangford Lough
Broad-scale Mapping
Current distribution based on MRRG surveys using ROV (115 sites) and diving (26 sites)
Probable historical distribution based on recorded data
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Horse Mussels in Strangford Lough

12. Detailed boundary mapping
Patches of reef will be mapped in detail to provide a baseline for future reference
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Horse Mussels in Strangford Lough

13. Horse Mussels in Strangford Lough
Monitoring
The research group will monitor condition of the reefs over time by recording:
fauna associated with the mussels
densities of the mussels
recruitment (settlement) of juvenile mussels
in good and compromised horse mussel beds in the north and south basins of Strangford Lough.
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Horse Mussels in Strangford Lough

14. Horse Mussels in Strangford Lough
Monitoring
GOOD
Mussels per m2
% Shell (green)
% Sand (red)
% Mussels (blue)
POOR
GOOD
POOR
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Horse Mussels in Strangford Lough

15. Horse Mussels in Strangford Lough
Intervention trials:
Translocation of Modiolus from outside the Lough
Deploying spat collectors and cultch
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Horse Mussels in Strangford Lough

16. Intervention trials: Aquaculture
LARVAL TANKS
SPAWNING TANKS
LARVAL DEVELOPMENT
ALGAL CULTURE
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Horse Mussels in Strangford Lough