Why we should be aiming for oyster reef restoration – and

Why we should be aiming for
oyster reef restoration –
how to do it?
Janet H Brown
Oyster workshop, Isle of Vilm, November 14-15th 2012
Background to work from 2009
• Call for proposals from SARF with 50% funding also
from SNH and The Crown Estate
• Development and delivery of a proposal for reestablishment, on a pilot scale, of a native
oyster population in Scotland
• Janet Brown, Liz Ashton and David Scott
• University of Stirling
Work carried out
• Bringing together all interested parties
• Steering group
• Technical review
• Ecosystem service and economics
• Site selection for restoration
• Funding sources
• Preparation of bids
Incomplete/anecdotal data suggest that exploitation
levels for some areas in the UK & NI prior to 1885
might have been 50-60 times higher
U.K. Landings of Ostrea edulis 1886-1990
[Gardner & Elliott 2001 NOSAP Review]
IBIS Workshop Dai R
Settlement patterns of oysters
• Preferred settlement
• Live oyster>dead oyster> anything else
• Under natural conditions this must mean
reef formation
Oyster spat settled on
adult oysters
“these oyster grounds
consisted of reefs built
of oysters, knitted and
interlaced with countless
other invertebrates. The
bottom of the North Sea
was hardened by a living
crust, something that
many scientists today
find hard to believe”
Roberts 2007
Pressures on native oysters
• Predation
• Disease
• Cold (extreme winters)
• Poor recruitment
• Fisheries – over fishing
• Pollution
Report of the Royal Commission
on Sea fisheries 1866
Read it and weep!
Largest oyster found – trawlers
• Found in Shetland at
depth of 120m (May
• 201mm and over 1kg wt
Benefits of reefs
• Broodstock concentration
• Disease • Conservation
– Cf Cranfield et al 2004-mutual benefits in
restoration between Ostrea and Modiolus
where over fishing has damaged habitat
Benefits of oyster restoration
Environmental benefits
• Reduce erosion
• Improve water quality
Socio-economic benefits
• Commercial fishery
• Community involvement
• Tourism
• Education
Benefits of oyster restoration
Environmental benefits
• Increased biodiversity
• Provide habitat and food
Method to be used in the Forth
This protects against
predators, allows
easier monitoring
Slide from Tony Legg, presented at ASSG conference October 2012
Study location
Loch Ryan
Menai Strait
Natural Analogue
Strangford Lough
Holistic experiment of oyster reefs v singletons
Comparison of Ostrea edulis in elevated broodstock modules with singletons on the seabed
May 2012‐June 2014 (tbc)
Poole Bay, south coast UK
24 elevated modules in clusters, 24 seabed modules
elevated modules ¾ filled with scrubbed and washed oyster shell as a base and completed with live O. edulis
‐ seabed modules contain live O. edulis only
Regular programme of sampling to establish benefits to:
‐ oyster growth and physiological performance
‐ gonad development rates and haemolymph vitellogenin
‐ larval recruitment to the water column and onto live oyster shell
‐ oyster epibiota, abundance and biodiversity
‐ biodiversity within module interstices
Antony Jensen
[email protected]
Chris Hauton
[email protected]
Helen Stevens
[email protected]
Original idea from Ostrea project www.ostrea.stir.ac.uk/
Oyster seabed ‘box’ next to
The development of an indicative, ecologically coherent network of sub-tidal Marine
Protected Areas (MPAs) in Bulgaria and Romania. Photo D Micu