Why we should be aiming for oyster reef restoration and how to do it?

Transcription

1 Why we should be aiming for oyster reef restoration and how to do it? Janet H Brown Oyster workshop, Isle of Vilm, November 14-15th 2012

2 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

3 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

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5 Incomplete/anecdotal data suggest that exploitation levels for some areas in the UK & NI prior to 1885 might have been times higher U.K. Landings of Ostrea edulis [Gardner & Elliott 2001 NOSAP Review] 22/11/2012 IBIS Workshop Dai R 5

6 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

7 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

8 Pressures on native oysters Predation Disease Cold (extreme winters) Poor recruitment Fisheries over fishing Pollution

9 Report of the Royal Commission on Sea fisheries 1866 Read it and weep!

10 Largest oyster found trawlers again! Found in Shetland at depth of 120m (May 2012) 201mm and over 1kg wt

11 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

12 Benefits of oyster restoration Environmental benefits Reduce erosion Improve water quality Socio-economic benefits Commercial fishery Community involvement Tourism Education

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14 Benefits of oyster restoration Environmental benefits Increased biodiversity Provide habitat and food

15 Method to be used in the Forth This protects against predators, allows easier monitoring

16 Slide from Tony Legg, presented at ASSG conference October 2012

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19 Study location Experimental Loch Ryan Menai Strait Solent Natural Analogue Strangford Lough

20 Holistic experiment of oyster reefs v singletons

21 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 Contacts: Antony Jensen acj@noc.soton.ac.uk Chris Hauton ch10@noc.soton.ac.uk Helen Stevens Helen.Stevens@naturalengland.org.uk Original idea from Ostrea project

22 Oyster seabed box next to blocks

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26 The development of an indicative, ecologically coherent network of sub-tidal Marine Protected Areas (MPAs) in Bulgaria and Romania. Photo D Micu

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