Management and Restoration Discussion
Background
An area outside of the lough (outer Ards Peninsula, Irish Sea) has been identified as
having Modiolus clumps that are biologically and genetically similar to the Strangford
population. The Queen’s University contract will determine the extent of the Outer Ards
Modiolus site and research its suitability as a donor site for the restoration of Strangford’s reefs.
In the intervening period since the award of the current contract, it has come to light that an
earlier restoration trial plot within Strangford Lough from 2010 has since failed. With our current
knowledge of Modiolus reefs and Strangford Lough, we think there are multiple important
questions to be addressed in determining future restoration. The findings of the workshop and
discussion points raised by delegates will help the Departments in determining if there is
significant value in proceeding with the project in its current form, or if as a result of the
continuing decline in the extent of the reefs within Strangford despite proactive management in
the form of mobile gear ban and restrictions on pot fishing, do we need to revise the restoration
plan.
Summary of comments to the following questions
Question: Should the original area of modiolus be amended from 18 to 10 km2
-General consensus that it should be what it was which seems to be 10km2 using the most recent
data. However, you should not to seem like you are trying to reduce area to get out of original
mandate.
Question: Can we predict if Lough would ever recover without intervention under current
management
-General consensus was that the Lough will not recover under the current management scheme.
Question: Are there restoration techniques other than translocation that could be used.
-Other techniques were suggested such as using a bivalve hatchery to supply modiolus and
restoring other reef forming bivalves. The best approach will likely be using all three approaches,
with translocation the only available technique in the short-term.
Question: Is it ethical to remove an intact reef to restore another area that should be protected in
its own right.
-The General consensus was that it is ethical if the donor site is not protected which will likely
result in it being degraded if it was not used as a donor site. In addition, it is ethical if the
transplanted mussels will likely survive. Mussels should not be removed from high density reefs,
but from unprotected and fragmented areas.
Suggested questions provided to discussion leaders:
a) Will Modiolus in SL (with or without restoration efforts) ever recover towards the
original 18 km2 baseline extent?
i) Can we predict if Modiolus would recover if we simply leave it alone with current
management?
(1) How long?
ii) Will Modiolus in SL ever recover towards the original 18 km2 baseline extent with
intervention?
(1) How long?
(2) Restoration efforts other than suggested translocation?
b) Do we think it is worth pursuing a restoration effort using translocation of donor clumps
from outside the lough (recognizing the plot sizes will be larger than the earlier 2010
experiment and therefore may be more likely to survive).
c) Is it ethical to remove a relatively intact Modiolus reef which some would argue should
be designated and protected in its own right?
d) Would the European Commission be satisfied with the concept of designating an
additional site while not initiating restoration activities at an existing damaged site?
e) Translocation methods
i) Maximum % of donor population can be removed?
ii) Methods used to translocate
iii) Size and number of reefs created
iv) Predator removal
f) Monitoring
i) What metrics should be used to determine if translocation efforts are successful?
(1) Measured within 2 years of current study
(2) % survival of transplants?
(3) Recruitment similar to measured previously?
Written notes of recorded conversation
Participant abbreviations:
Howard Platt-HP
Mark McCaughan – MM
Joe Breen – JB
Mark Emmerson -ME
Bjoern Elsaesser – BE
Bob Brown – BB
Bill Sanderson - BS
Danny ONeill- DO
Lynn Gilmore – LG
Julia Sigwart – JS
Jose Farinas-Franco –JFF
Kim Last – KL
Ian Montgomery – IM
Bernard Picton – BP
Jade Berman – JBe
Matt Service – MS
Claire Goodwin – CG
Nate Geraldi – NG
Hugh Edwards – HE
Tim Mackie – TM
Henk van Rein - HVR
Kirsten Ramsey –KR
Colin Armstrong – CA
Julia Calderwood - JC
JB and BB were discussion leaders
Discussion
Overview of questions – BB
Modiolus board here in Strangford Lough (SL) will take into account comments from today into
consideration. Not goal of translocation to destroy existing habitat to restore SL. Point is to pick
everyone’s brain. – BB
Point is to come up with resolution, which can be brought to SL steering group. Submitted
revised restoration plan after complaint by Ulster Wildlife. Goal is to bring SL back into
favorable condition. Recent data from surveys indicate modiolus is not recovering in SL-JB
Should we address cost of projects first, government funding is limited –HP
Let’s wait to address cost, very expensive to restore 18km2 of reef. -JB
Translocation project could be helped by fisherman, different ways to get other funding (EFF,
Natura 2015). But need to define project. -MM
Hope to have viable population, not just translocate – BB
Get project then talk about funding - JB
Different avenues to get funding don’t need to depend on Government. Many resources, many
types of careers within room, work together for funding– ME
Should consider cost last –JB
Question: Should the original area of modiolus be amended from 18 to 10km2. -JB
Know little about ecosystem in SL, ground truth recent map of SL, use SMILE, connectivity
with Irish Sea, and other examples of existing data to fill knowledge gaps. Don’t know if
modiolus will survive in current ecosystem. What is the point? Can you convince public? Focus
on big picture, more than just modiolus. – BE
EU commission has set a goal, what have we done so far? Decide if we can restore modiolus.
DO we need to kick start restoration with translocation. Will take a long time. – JB
Don’t know outcome until end of studies – BE
Have spent a lot of money on modiolus studies, but can compare to benefit of fisheries that we
have lost. - BB
Agree, need to know ecosystem. Could use ecosystem services to highlight importance of SL
health. Example of complex seagrass restoration effort. Need good understanding of ecosystem –
BS
Agreed, we can do things independently by addressing unknowns. Try and reduce original
estimate of modiolus reef area (18km2) – ME
Question: Should baseline of modiolus reef area be amended to 10km2 from 18km2.
Need to revise number from 18 to 10km using this discussion and hind casting (James Strong),
new substrate mapping (Annika Clements) – JB
Lower number is more accurate. Not going to alter restoration effort, but inform EU commission
on trajectory to favorable status – BB
SL was formally designated in 2005 –JB
Will commission allow a change in reef area? –Unknown
Modiolus is now getting a lot of attention after recognized in SL. Look at SLECI results for
current status of SL. Restore reefs, regardless of reef. –BP
Look at ecosystem models, do not have SL data in one place. Look at stressors-MS
Should baseline of modiolus reef area be amended to 10km2 from 18km2. EU commissions want
to see “favorable status”. Could Outer Ards be designated as protected in place of SL. Details on
different habitats specified in designation, more than just modiolus. Commission wants to see
conservation of feature, not SL- JB
May not want to reduce baseline area of Modiolus reef, give less leverage. Useful to look at
other reef forming species. Who will pay infraction fine. –DO
Any infraction fine will come from tax payer. –JB
Explained methods of estimating reef at 18km2. Used best data available, outlined existing reefs,
but modiolus is very patchy. But likely an overestimate –BB
Why is it important how much reef existed? –DO
1976 is the baseline for how much reef existed. Important because that is what is the ultimate
goal and should be within the range what existed naturally. –JB
Estimate should be what existed. – LG
Need true map in 1976 to set baseline.-JB
Need to map Outer Ards so that this issue does not occur again. –MS
Do we know approximate area of Outer Ards reefs. –CG
Gross estimate for Outer Ards is 2.5km2 – NG
Biggest reef in Scotland is 3.5 km2, all reefs not more than 10km2. In Wales largest around
3.7km2. 18 is huge compared to others. BS
Is there protection for Outer Ards reefs – Unknown
Protection measures are under way. -JB
Next question – can we predict if Lough would ever recover without intervention under current
management – BB
No, it is an issue of too much sedimentation. Need to reduce sedimentation for recovery – JS
No, sedimentation is an issue –JFF
Need small scale restoration to test if Modiolus can survive. Control some variables –MM
Use small scale manipulation to determine what are the important stressors. Could use oysters as
substitute – BS
Background on the speakers experience with cultivating oysters in Strangford Lough. Grow fine,
but once at significant densities, oysters would die from disease. Favor trying other bivalves, but
oysters may not be right animal– MM
How many modiolus exist in SL? Are they healthy? Are modiolus viable in SL? – KL
Yes, at least during original MRRG, especially in southern SL. Most individuals older than 30
years. -JFF
We do not know enough to say “Never”, never say never. The SL will not likely restore itself, it
will need intervention. Have a sample size of 1 for restoration effort, need bigger sample size.
Restoration will be long and expensive. Ecosystem services are good way to sell importance of
habitats. Has been an indirect effect of unregulated fishing - IM
Fisheries are regulated now – MM
Fishing ban is in effect in SL and should move forward. –JB
SL is warm in summer but waters are warmer in Norway as stated by BB. –Unknown
Look at local modiolus population temperature tolerance. –same as above.
Next question – Are there restoration efforts other than translocation that could be used.
Restore other parts of the ecosystem, such as reverse changes in sedimentation. Sedimentation
may already be reduced- BE
Fresh water input very little. –MS
Asked BS for examples in Scotland where sedimentation may be an issue. -JB.
Not really, but example where forest was cleared and modiolus was reduced. –BS
SLECI did not find evidence that sedimentation was an issue. -JB
Monitoring could answer whether sedimentation is an issue for modiolus – ME
Do monitor nutrients in SL. –MS
Can we compare to historic rates? –BP
No. -JB and -BB
Artificial reproduction of modiolus could be an alternative. Larne shellfish hatchery has had
some success in modiolus reproduction. Could populate with hatchery reared modiolus. – MM
Worth investigating potential for artificial reproduction, because lough will not recover without
intervention – JB
Need publication to verify findings. –ME
Restoration efforts should target south SL. -HE
Need to model recipient site and how many. –JB
More than just modiolus to consider, many other species in SL. -BB
Aquaculture could help restoration efforts. Had tanks of modiolus at QML. -LG
Make subtidal modiolus trestle to protect modiolus and use as seed populations. –ME
What density to stock restoration site? 50 -200 adults per m2. –TM
Restoration is complicated and we will use all available data to choose sites, size and density of
restored reefs. Need to consider feasibility of protection of restored reefs.
Seeding small population. –BB
Using translocation and artificial seeding is best option. But will take time. Protect Outer Ards
also. Use models to determine if Outer Ards larvae come into SL-JB
Need more than 1 restoration site. -MM
What about starfish predation? Need to account for predation of translocated modiolus. –HVR
Will consider predator removal techniques. –JB
Even with successful translocation will not restore to 10km2. Is restoring other species an
option-DO
Designation is “reef” not necessarily modiolus. This is an option. Substrates and shapes likely
vary. –JB
Experiment on different substrates and sizes. –DO
Are other examples of reefs. –JB
Ecosystem services are a good selling point. Habitats can be very different, but have same effect.
–BS
Do have scallop shells. -MM
Long-term goal of restoring modiolus. Don’t return to commission with excuses. –JBe
Models do exist to determine larval transport into SL. -MS
Commission may not accept any “reef”, example in Wadden Sea. May need modiolus reefs,
others may not be equivalent. –JBe
Objectives of commission can be changed. –JB
Need to show good will. –BS
Not de-designate, still trying to turn SL to recovery. JB
Very long-term. Be careful about what is “artificial”.-JFF
Can restoring other reefs reduce chance of restoring modiolus? –KR
Artificial reefs are in parallel with other efforts. –JB
Artificial reefs may facilitate restoration effort. To much focus on modiolus restoration-BP
Modiolus can exist on rocks. -BB
Create habitat with rugosity. –BS
Need heterogeneous habitat. –KR
Species have decreased and increase, look at SLECI report. -JB
Artificial reefs good idea for biodiversity. Don’t put where modiolus could exist. –JBE
Designation of SL has many species and not surveyed for a while, perhaps check old records.-JS
SL is complex and may be is some form of early succession to recovery. Weedy species could be
tunicates. –BB
Next question –Is it ethical to remove an intact reef to restore another area that should be
protected in its own right
Both departments (DOE and DARD) do plan on initiating plans to protect the Outer Ards reefs in
the near future (make them SAC’s). We plan on removing the outer edges of the reefs after
accurate mapping. It this type of mapping possible? Is it ethical to remove?- JB
May not be ethical if we don’t know if they can survive in SL. – TM
Removal well be very small proportion of reef, transplant 240 m2 or 3 km2 or the reefs.
About .2-.5% of the modiolus on one of the reefs would be transplanted. NG
Reefs in Donaghadee Sound so could get modiolus elsewhere. Could be infaunal as well. Should
map those areas as well- CG
Very small proportion of population, in grander scale will that affect the reefs? – ME
Contingent on whether it is likely that transplants will survive? BS
But they are not protected and donor site will likely degrade anyway. –TM
Agreed. Could we use bicatch from fisheries without incentivizing there harvest? – BS
Shouldn’t damage good site to prop-up very damaged site. Likely enough degraded sites along
Outer Ards to supply transplantation. Dependent on good survey. Should not remove core of
reefs– BB
Never planned to remove large solid reefs. Previous dives found fragmented habitat from
trawling along perimeter of reefs. Identify fragmented reef and technology is there. Can’t be
removed transplanted.– JB
Why would survive in SL if not along Outer Ards? – KR
Increase survival by consolidating in to larger reef, predator removal and have protection. -JB
Predator control has been discussed – JB
Predators will be monitored frequently (once a week) right after transplantation to determine if
we need to remove predators. - NG
Astro-turf fences could be used. – JB
May need to allow byssus threads to form on tresses before setting them to reduce chance of
mortality from sedimentation. – MS
Modiolus quite tolerant to sedimentation. – BB
Perhaps not when clumped. – MS
Findings will be presented that modiolus clump in less than a week, which is a shorter time scale
than sedimentation could occur. – NG
The schedule is to conduct transplantation this summer. Is this to fast? Do we need more
research? – JB
Fragmented edges may help to buffer reef center from damage. –JBe
Does Ulster Wildlife not support translocation? - JB
Personally does not want to damage good site but will have to talk to board to get Ulster wildlife
stance on translocation. How far does the translocation go towards restoring the 10 or 18 km2 of
modiolus habitat? - JBe
Ulster Wildlife trust’s input will be very important for EU commission - JB
Need position from Ulster Wildlife. - MM.
Translocation is the decision of the restoration group. - CA
Should be careful of not doing anything. If no translocation then what? Aquaculture? Should
have long-term plan. - ME
Good to source modiolus from fished areas, because they are likely to be damaged. Are the
donor areas not going to be protected?– BS
Do seed mussels fishers catch modiolus? – JB
Gives background on seed mussel fishery. How they discovered modiolus along outer ards. May
take a small amount of modiolus but hasn’t seen them. 60% of catch not seed mussel-MM
Core of reefs will likely be protected, while seed mussel fishery works around the areas. –BB
May be very small patches, but not sure. Many different users that have altered habitat. Modiolus
not likely in Donaghadee Sound, has been heavily fished-MM
There are good patches in Donaghadee Sound. Dived it recently. –CG
Work with fisherman to relay Modiolus. –LG
Always the plan. – JB
Ethically not right to remove intact reefs from an SAC?- JB
Could run small scale experiments. Good to run small scale experiment to determine if
translocation is viable. It is worth removing small number. – HE
Never idea to remove large numbers. Need to determine viability of modiolus in SL– JB
No an easy decision. But removing very small presentation of population there is not other way
than translocation to determine viability of modiolus in SL. If small removal does hurt donor
reefs than those reefs are likely degrading regardless. – NG
Anyone have burning issues against permitting suggested translocation. – JB
Are there experiments that indicate how much could be removed without hurting donor
population. ME
Removing this small amount will not affect the integrity of the donor sites. -JB
Need detailed map of donor area. –BB
Modiolus will be dredged which is a large stressor. Should have controls and put back down
along outside. –KL
Was discussed, but have to weigh urgency and morality. -JB
Less than 24 hours does not seem to affect blue mussel .-JC.
Surprising, given that they are intertidal species. -BE
Blue mussels are both intertidal and subtidal so it is context dependent. – ME
Fishery does have stressors but is clearly viable. - MM