VS & Mussel culture in relation to Nature conservation Coastal examples and offshore perspectives. Henrice Jansen, 14 March, Berlin

Transcription

1 Culture VS & Nature Mussel culture in relation to Nature conservation Coastal examples and offshore perspectives Henrice Jansen, 14 March, Berlin

2 Mussel culture in coastal areas Waddensea? Oosetrschelde 2

3 Mussel culture in coastal areas Traditional: Bottom culture New: Seed collection through suspended mussel seed collectors Extensive cultures Depends on nature for feed, seed and space Based on nature > depending on nature

4 Culture in Nature reserves Engagement of NGO s Transition 2008 Licence to produce

5 Nature conservation Biodiversity in the Waddensea Carrying capacity in the Eastern scheld estuary

6 Biodiversity Mussel culture cycle All sublittoral From mussel seed To culture plots 6

7 Biodiversity related to mussels Associated fauna Food for birds 7

8 Biodiversity Effects Seed fishery Mussel seed is fished on wild sublittoral beds by bottom dredging after new spatfall in: autumn on unstable beds (green), and next spring on relatively stable beds (red) Fishery may disrupt benthic habitats including their natural values In case of doubt: no N2000 permit 8

9 Suction dredge Box core Impact Control before after, control impact (BACI)

10 Biodiversity Effects Seed fishery Mussel biomass Autumn fishery: decrease of mussel biomass, no significant difference between fished and control plots Spring fishery: significant difference, lower biomass for 2 years after fishery on fished plots After 3 years no difference impact and control sites: wild mussel beds have limited longevity, no dramatic fishery impact 10

11 Biodiversity Mussel biomass Mussel fisheries on instable natural banks to bottom plots with high survival 27% more mussel biomass in the Waddensea E.g. Eider ducks feed on mussel plots

12 Biodiversity - wild beds vs culture plots Nr of species M O All stations Without M & O Nr of samples Survey on wild mussel beds, oyster beds, and mussel culture plots; : 568 stations in 3 yrs shellfish beds = biodiversity hot spots

13 Biodiversity - wild beds vs culture plots Total 108 species in 159 box cores 84 species on wild beds (5 unique) 102 species on mussel culture plots (23 unique) 16 species were invasive and were all found in both habitats Typical species: wild: barnacles, sea anemones culture: ragworm, crab, starfish

14 Biodiversity Conclusions Mussel beds are biodiversity hot spots More mussels on culture plots More biodiversity on culture plots Wild beds sensitive to predation, better survival in low salinity areas, with lower biodiversity Fishery impact less dramatic than originally thought: maintenance activity by the farmers enhances survival Paves the way to combine exploitation and nature conservation: Profit and Planet 14

15 Carrying capacity - definition How much production can an ecosystem support without causing negative impacts

16 Carrying capacity - definition Productie Primaire productie (groei) Fytoplankton (bestand) Aanvoer Wateruitwisseling Verblijftijden Voedsel Productie draagkracht Ecologische draagkracht Mosselbestand (hoeveel, waar) Visgewichten Kweek Mosselen Overige Schelpdieren Oesters, Ensis, kokkels etc Hardsubstraat Zoöplankton Predatie Natuurlijke sterfte, zaadval 16

17 Carrying capacity - Indicators Primary production Voedsel Food concentrations Meat yield mussels Kweek Mosselen Overige Schelpdieren Stocks 17

18 Carrying capacity indicators OS Carrying capacity is food dependent No recent PP data available > therefore proxies : reduction PP Increase in Oyster stock 2010 now: lack of pp data decrease in wild stocks Less chances for over exploitation of food sources high meat yields? 18

19 Carrying capacity indices Production Time PT Time to renew phytoplankton biomass Residence Time RT Time to renew watermass Clearance Time CT Time it takes to filter entire water volme Algae biomass PP Tidal volume Total volume system CR Biomassa Filter Feeder populatie Watervolume systeem Clearance ratio Grazing ratio CT RT CT PT CT/RT <1= impact CT/PT <1 = impact ASC: CT/PT>3 (for commercial stocks) 19

20 Carrying capacity indices gebied land code dominante soort RT PT CT CT/RT CT/PT ref Beatrix Bay NwZl BB mossel Gibbs, 2007 Boughton CAN BOUG mossel Filgueira et al, 2015 Brudenell/ Montague CAN MON mossel Filgueira et al, Cardigan CAN CAR mossel Filgueira et al, 2015 Carlingford Lough IERLAND CL mossel, oester Ball et al., 1997 Cascumpeque CAN CAS mossel Filgueira et al, 2015 Chesapeake Bay USA CB oester Newell, 1988 Clew Bay IERLAND CLB mossel, oester keyzone project Delaware Bay USA DB oester Biggs & Howell, 1984 Grand Entre e CAN ENTRE mossel Filgueira et al, 2015 Limfjord/Lögstör Broad DK LL mossel Dolmer 2002 Loch Creran UK LC oester keyzone project Lunenburg CAN LUN mossel Filgueira et al, 2015 Malpeque CAN MAL mossel Filgueira et al, 2015 Marennes-Oléron F MO mossel, oester Bacher, 1989 Murray CAN MUR mosel Filgueira et al, 2015 Narragansett Bay USA NB Mercenaria Kremer & Nixon, New London CAN LON mossel Filgueira et al, 2015 North Inlet USA NI oester Dame et al., 1980 Oosterschelde <1995 NL OS95 mossel, kokkel Smaal et al., 2001 Oosterschelde NL OS09 mossel, kokkel, oes Smaal et al., 2013 Ria de Arosa SP RA mossel Tenore et al., 1982 Savage CAN SAV mossel Filgueira et al, 2015 Ship CAN SHP mossel Filgueira et al, 2015 South San Francisco Bay USA SSB diverse Cloern, 1982 St. Ann s CAN ANN mossel Filgueira et al, 2015 St. Mary s CAN MAR mossel Filgueira et al, 2015 St. Peter s CAN PET mossel Filgueira et al, 2015 Sylt (Kőnigshafen) GER SY mossel, kokkel Asmus et al., 1990 Tracadie CAN TRAC mossel Filgueira et al, 2015 Wadenzee-west NL WZw mossel Dame et al., 1991 Whitehead CAN WHITE mossel Filgueira et al,

21 Culture versus/and Nature - conclusions Mussel culture is extensive Nature values can be enhanced Shellfish culture may link to nature management Ecosystem impacts vs ecosystem services 21

22 Coastal vs Offshore: some perspectives

23 Coastal vs Offshore: some perspectives Coastal Crowed Culture in Nature reserves: Strong NGO opposition Efficient (cheap) production High nutrient load (eutrophication control) Chances for nature mananegment Offshore Relatively large areas Other users Multi-use combinations? Cummulative Impact assessment Expensive production methods. From bottom to suspended Low nutrients, high currents (carrying capacity) Habitat provisioning More fuel use Regulatory frameworks 23

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