mussel powered living shorelines for salt marsh erosion control
MUSSEL POWERED LIVING SHORELINES FOR SALT MARSH EROSION CONTROL Delaware Estuary Living Shoreline Initiative Delaware Estuary Living Shoreline Initiative (DELSI)
David Bushek, Danielle Kreeger, Laura Whalen Joshua Moody Laura Whalen, Joshua Moody, Angela Padeletti
Erosion and accretion are natural processes that create dynamic habitats. Erosion in the mouth of the Maurice River. Note the loss of meander around Fowlers Island and Basket Flats around Fowlers Island and Basket Flats
Erosion threatens marshes and upland habitats, including developed properties. Erosion is accelerated by boat wakes, sea level rise, storms and other factors. Erosion control will become increasingly difficult with sea level rise and continue to be a long‐term problem in coastal areas.
Hardening the shoreline is like hardening your arteries hardening your arteries……
Shellfish as Natural Erosion Control South Carolina
New Jersey
No intertidal oyster reefs in Delaware Bay NJDEP reluctant to support oyster restoration, banned ‘shellfish shellfish gardening gardening’ in in closed waters g g y gy p Fringing oyster reefs absorb wave energy and trap sediments. Oyster reefs also create habitat, filter water, and recycle nutrients.
Ribbed Mussels: An Alternative To Oysters Similar ecological services – – – –
Stabilize sediments Water filtration Nutrient cycling Sediment deposition Sediment deposition
Not harvested – No poaching concerns N hi – No human health risk
Synergism with grass forms levees Geukensia demissa
Can combine with other tactics
Delaware Estuary Living Shoreline Initiative (DELSI) Purpose: p identify living shoreline methods for Delaware Bay Questions: 1) Can coir biologs and and mats halt salt marsh erosion? halt salt marsh erosion? 2) Can ribbed mussels help?
Phase I Low energy
Intermediate High energy
Test installation methods Test installation methods across a gradient of energy and erosion.
DELSI Deployment
Installed multiple configurations. configurations Total station surveys tied installations to local tied installations to local USGS benchmarks. Established transects to Established transects to monitor change.
Grass and mussels survived when planted in logs
Initial monitoring provided exciting results….
Juvenile mussels il l recruited to coir logs… …sediment trapping with rich mats of microphytobenthos
… the excitement was palpable
But a few months later …..
Few logs remain at two sites. Marsh retreat was evident Marsh retreat was evident. Deflated logs = Deflated enthusiasm g
But the third site looked great! Sediment accumulated Sediment accumulated behind most logs
Closing off ‘scallops’ worked best …enthusiasm restored!
Energy and biolog gy g survival Coir Log Survival
Relative Energy at DELSI Sites Yokoyama et. al. 2004
Logs Survived
12 10
14 12
Q Quantified energy gy as 6dissolution of plaster 4hemisspheres
Logs Moved or Deflated
8
10
# of Logs
P Plaster‐o‐p paris dissolution index
16
8 6 4 2
2
0
0
Lowest at site D
B
C
D
B
Maurice River DELSI Sites
C Maurice River DELSI Sites
Logs and mats survived best at low energy site Logs and mats survived best at low energy site Logs did not work if tucked against marsh Logs survived best when lined with oyster shell bags
D
What configuration worked best? worked best? % Sedim ment Elevation In ncrease
120 100 80 60 40 20 0 Log
Double Log
Shellbag + Log
Treatment Type
Control
DELSI Phase 1 Conclusions
Coir biolog treatments: • attenuated waves • reduced erosion • trapped sediments • produced microphytobenthos • attracted mussels attracted mussels • amenable to seeding Optimal configuration: Optimal configuration: Double logs over mat with shell bags in front
Phase 2 h Install mat
Reinforce with shell bags
Replicate successful treatment method treatment method Add grass and mussels Quantify faunal use
Install logs
Let sediment accumulate
Plant grass: Nursery plugs Salvaged clumps
Apply Mussels Three sizes < 1 cm < 2 cm > 2 cm
Two densities high low
Mussels applied in August 2010, moved into logs by November. November But method is cumbersome.
Four installations completed July 2010 Monitor: Sediments Grass Fauna
Motile Fauna Seines: deployed at high tide (in pairs) retreived at low tide
Minnow pots: deployed at low tide (10 per trt/ctrl) retrieved at low tide 24 hrs later
Seine Catch Data Control Treatment 1037 1536
Blue Crab Blue Crab
647
501
Mummichog Bay Anchovy White Perch White Perch Silverside Silver Perch W kfi h Weakfish Striped bass Black drum Wi Window pane flounder d fl d Atlantic menhaden Hogchoker American eel Spot Unidentified Summer Flounder Naked Gobi Toadfish
221 251 89 50 9 16 14 12 12 1 5 2 2 2 1 1
229 26 52 38 26 15 8 6
Seine Biomass 2000
Control
Treatment
1800
4
1600 1400
1 1 1 1
Bimass (gg)
Seine Species Grass Shrimp
1200
*
1000 800 600 400 200
N=8
N=4
N=4
Summer
Fall
0
1
All
Minnow Pot Species Control Treatment Mummichog 544 1564 458 14 1 6 3 1 2 1
424 6 9 2 3 2
Minnow Pot Biomass 160
Control
Treatment
140 120 Biomass (g))
Minnow Pot Catch Data
Grass Shrimp American eel White Perch Blue Crab Silver Perch p j Spotfin mojarra Bunker Striped Bass
100 80 60 40 20 0 All
Summer
Fall
DELSI Summary
Next Steps
• Biologs provide a novel tactic for Delaware Bay
• Continue monitoring and assessment
• Trap sediments well
• Develop mussel integration methods and methods and validate/quantify their rol
• Grass and mussel plantings survive i
• Expand sites • FFaunal use is similar to l i i il t natural marsh
• Practitioners guide
Thanks to our funding agencies and field crews!
David Bushek, Danielle Kreeger, Laura Whalen Joshua Moody Laura Whalen, Joshua Moody, Angela Padeletti
Erosion and accretion are natural processes that create dynamic habitats. Erosion in the mouth of the Maurice River. Note the loss of meander around Fowlers Island and Basket Flats around Fowlers Island and Basket Flats
Erosion threatens marshes and upland habitats, including developed properties. Erosion is accelerated by boat wakes, sea level rise, storms and other factors. Erosion control will become increasingly difficult with sea level rise and continue to be a long‐term problem in coastal areas.
Hardening the shoreline is like hardening your arteries hardening your arteries……
Shellfish as Natural Erosion Control South Carolina
New Jersey
No intertidal oyster reefs in Delaware Bay NJDEP reluctant to support oyster restoration, banned ‘shellfish shellfish gardening gardening’ in in closed waters g g y gy p Fringing oyster reefs absorb wave energy and trap sediments. Oyster reefs also create habitat, filter water, and recycle nutrients.
Ribbed Mussels: An Alternative To Oysters Similar ecological services – – – –
Stabilize sediments Water filtration Nutrient cycling Sediment deposition Sediment deposition
Not harvested – No poaching concerns N hi – No human health risk
Synergism with grass forms levees Geukensia demissa
Can combine with other tactics
Delaware Estuary Living Shoreline Initiative (DELSI) Purpose: p identify living shoreline methods for Delaware Bay Questions: 1) Can coir biologs and and mats halt salt marsh erosion? halt salt marsh erosion? 2) Can ribbed mussels help?
Phase I Low energy
Intermediate High energy
Test installation methods Test installation methods across a gradient of energy and erosion.
DELSI Deployment
Installed multiple configurations. configurations Total station surveys tied installations to local tied installations to local USGS benchmarks. Established transects to Established transects to monitor change.
Grass and mussels survived when planted in logs
Initial monitoring provided exciting results….
Juvenile mussels il l recruited to coir logs… …sediment trapping with rich mats of microphytobenthos
… the excitement was palpable
But a few months later …..
Few logs remain at two sites. Marsh retreat was evident Marsh retreat was evident. Deflated logs = Deflated enthusiasm g
But the third site looked great! Sediment accumulated Sediment accumulated behind most logs
Closing off ‘scallops’ worked best …enthusiasm restored!
Energy and biolog gy g survival Coir Log Survival
Relative Energy at DELSI Sites Yokoyama et. al. 2004
Logs Survived
12 10
14 12
Q Quantified energy gy as 6dissolution of plaster 4hemisspheres
Logs Moved or Deflated
8
10
# of Logs
P Plaster‐o‐p paris dissolution index
16
8 6 4 2
2
0
0
Lowest at site D
B
C
D
B
Maurice River DELSI Sites
C Maurice River DELSI Sites
Logs and mats survived best at low energy site Logs and mats survived best at low energy site Logs did not work if tucked against marsh Logs survived best when lined with oyster shell bags
D
What configuration worked best? worked best? % Sedim ment Elevation In ncrease
120 100 80 60 40 20 0 Log
Double Log
Shellbag + Log
Treatment Type
Control
DELSI Phase 1 Conclusions
Coir biolog treatments: • attenuated waves • reduced erosion • trapped sediments • produced microphytobenthos • attracted mussels attracted mussels • amenable to seeding Optimal configuration: Optimal configuration: Double logs over mat with shell bags in front
Phase 2 h Install mat
Reinforce with shell bags
Replicate successful treatment method treatment method Add grass and mussels Quantify faunal use
Install logs
Let sediment accumulate
Plant grass: Nursery plugs Salvaged clumps
Apply Mussels Three sizes < 1 cm < 2 cm > 2 cm
Two densities high low
Mussels applied in August 2010, moved into logs by November. November But method is cumbersome.
Four installations completed July 2010 Monitor: Sediments Grass Fauna
Motile Fauna Seines: deployed at high tide (in pairs) retreived at low tide
Minnow pots: deployed at low tide (10 per trt/ctrl) retrieved at low tide 24 hrs later
Seine Catch Data Control Treatment 1037 1536
Blue Crab Blue Crab
647
501
Mummichog Bay Anchovy White Perch White Perch Silverside Silver Perch W kfi h Weakfish Striped bass Black drum Wi Window pane flounder d fl d Atlantic menhaden Hogchoker American eel Spot Unidentified Summer Flounder Naked Gobi Toadfish
221 251 89 50 9 16 14 12 12 1 5 2 2 2 1 1
229 26 52 38 26 15 8 6
Seine Biomass 2000
Control
Treatment
1800
4
1600 1400
1 1 1 1
Bimass (gg)
Seine Species Grass Shrimp
1200
*
1000 800 600 400 200
N=8
N=4
N=4
Summer
Fall
0
1
All
Minnow Pot Species Control Treatment Mummichog 544 1564 458 14 1 6 3 1 2 1
424 6 9 2 3 2
Minnow Pot Biomass 160
Control
Treatment
140 120 Biomass (g))
Minnow Pot Catch Data
Grass Shrimp American eel White Perch Blue Crab Silver Perch p j Spotfin mojarra Bunker Striped Bass
100 80 60 40 20 0 All
Summer
Fall
DELSI Summary
Next Steps
• Biologs provide a novel tactic for Delaware Bay
• Continue monitoring and assessment
• Trap sediments well
• Develop mussel integration methods and methods and validate/quantify their rol
• Grass and mussel plantings survive i
• Expand sites • FFaunal use is similar to l i i il t natural marsh
• Practitioners guide
Thanks to our funding agencies and field crews!
