Blue Collar Bivalves, Water Quality and Project ROI

Danielle Kreeger, Josh Moody, Kurt Cheng and Dave Bushek

Bivalves of the Delaware

Crassostrea virginica

Elliptio complanata

Geukensia demissa

Alasmidontaheterodon

Mya arenaria

Anodonta implicata

Mytilus edulis

Ensis directus

Mercenaria mercenaria

Leptodea ochracea

Nature’s Benefits (Natural Capital)

Shellfish for Cleaner Water

Start

3 Hours

FreshwaterMussels

RibbedMussels Oysters

Freshwater Mussels:  most imperiled

Oysters: prone to disease and salinity

Ribbed Mussels: losing marsh habitat

Bivalve Population Declines

Shellplanting for OystersPropagate and Reintroduce Mussels

Riparian Restoration

Fish Passage Restoration

Water Quality & Flow Management

•

Monitoring & Research

Living Shorelines

Tech to Restore Shellfish Now Exists

Living Shorelines

Funding and Capacity are Limited

http://delawareestuary.org/science_programs_state_of_the_estuary_treb.asp

Which Species is Best?

8

Which Tactic is Best?

Species Comparison

9

• Physiological Capacity

• Population Carrying Capacity

• Ecological Barriers

• Policy Barriers

• Willingness to Pay

Bivalve Feeding  Physiology

Goal: satisfy nutritional demands from seston supply

Organismal Needs:Energy (C)Essential biochemicalsVariation:  ‐ seasonal

‐ ontogenetic

Environmental Constraints:Food Quantity and QualityTemperatureVariation:  ‐ seasonal

‐ spatial

Feeding Rate Comparison

Approach:

• Natural Diets • Consistent Methods (30 yrs)• Seasonal experiments • Ambient temperatures

GametogenesisConditioning

Seasonal Physiology Cycle

Feeding Rate Comparison10 Species – fresh, brackish, salt

ConditioningOregonMussels

AlleghenyMussels

BrandywineMussels

New JerseyAsian Clams

Cheng 2015

Canary Creek

Ribbed Mussels

Kreeger 1986; 

Moody 2016

Kreeger1986

Kreeger and Howard 2011 Kreeger 2001 Kreeger and Gatenby 2002

Clearance Rates – Temperatures >20oCC

lear

ance

Rat

e (L

h-1

g-1

±SE

)

0 .0

0.5

1.0

1.5

2.0

Freshwater M usselN on-N ative C lamSaltwater Species

Marg. fa

lc.

Anod. calif.

Gonid. ang.

n=47

n=6

Lasmi. c

ost.

Elip. c

omp.Elip

. dilit

.

Act. lig

am.

Corb. fl

um.Geuk.

dem.

n=34

n=20

n=20

n=16

n=23

n=25 n=

25

n=90

n=20

n=11

9 Species: 0.5 ‐ 1.6 L/hr/g

Cle

aran

ce R

ate

(L h

-1 g

-1 ±

SE)

0 .0

0 .5

1 .0

1 .5

2 .0

F reshwa te r M usse lN on -N a tive C lamS a ltw a te r S pe c ies

Marg. fa

lc.

Anod. calif.

Gonid. ang.

n= 47

n=38

Anod. ore

g.

Corb. fl

um.Geuk.

dem.

n=23

n=13

n=80

n=25 n=

25

n=3n=

15

n=8

Crass

. virg

.

7 Species: 0.3 ‐ 1.6 L/hr/g

Clearance Rates – Temperatures 15 ‐ 20oC

Cle

aran

ce R

ate

(L h

-1 g

-1 ±

SE)

0 .0

0 .5

1 .0

1 .5

2 .0

F re s h w a te r M u s s e lN o n -N a tive C la mS a ltw a te r S p e c ie s

Marg. fa

lc.

Anod. calif.

Gonid. ang.

n = 4 7

n=38

Anod. ore

g.

Corb. fl

um.

Geuk. dem.

n=31

n=5

n=26

n=25 n=

25

n=56

n=12

n=1

6 Species: 0.1 ‐ 0.8 L/hr/g

Clearance Rates – Temperatures < 15oC

Month

2 3 4 5 6 7 8 9 10 11 120

30

60

90

120

150

180

0

20

40

60

80

100

TSS

(mg/

L)O

rganic Content

(%)

Seston Composition Highly Variable

Filtration Rates – Temperatures >20oC

8 Species:  1 ‐ 314 mg/hr/g

Filtr

atio

n R

ate

(mg

h-1 g

-1 ±

SE)

0

50

200

300Freshwater M usse lN on-N ative C lamSaltwater Species

Marg. fa

lc.

Anod. calif.

Gonid. ang.

n=38

Ellip. d

il.

Corb. fl

um.Geuk.

dem.

n=20

n=6

n=26 n=

23

n=90

n=11

n=20

n=20

Lasmig. c

ost.

Actin. li

g.

n=16

Physiological Findings

18

• Clearance rates of water were comparable among freshwater, brackish and marine species when normalized for body size and temperature

• Filtration rates of particles and associated pollutants depends largely on particle abundance and composition

• Models of biofiltration services can be constructed with data on:• Body Size and Abundance (Dry Tissue Mass)• Temperature (Season)• Seston Composition (TSS, %Organics, Nutrients)

Shellfish Strategies

19

• Increase suitable habitat e.g. oyster shellplanting, stream bed stabilization

• Enhance population abundance e.g. hatchery propagation, reseeding

• Alleviate stressors e.g. flows for salinity control, stormwater

• Improve growing conditions e.g. remove dams, sustain food quality

Considerations

20

• Track Record of Success How sustainable are the outcomes?Would carrying capacity be exceeded?  

• Geospatial NichesWhat is the nexus between pollutants and species niches?Where would shellfish enhancements be most effective?

• Policy and Interest BarriersAre there restrictions on commercial species?Is there sufficient interest in noncommercial species?

• Cost

Three Case Studies

21

Alewife floaters Anodonta implicata

Ribbed musselsGeukensia demissa

Oysters Crassostrea virginica

Alewife Floaters

22

A functional co‐dominant in tidal Delaware River

Anodontaimplicata

Population Biomass by Species Densities up to 100 per square meter

=10 tons dry TSS per hectare per year

Physiologically‐Based BioFiltration Estimates

Bed Clearance 

Rate

TSS Filtration

(L hr‐1 g   DTW‐1)

(gal day‐1 

g DTW‐1)(gal day‐1)

(kg DW day‐1)

Site 1 4,230 23,163 74,210 411,867 7.8

Site 2 18,648 477,389 992,074 5,506,008 104.2

Site 3 13,983 256,560 241,151 1,338,387 25.3

Site 4 35,525 1,662,570 586,163 3,253,202 61.6

Total 72,386 2,419,682 1,893,597 10,509,464 198.9

0.875 5.55

LocationArea (m2)

Number Tissue Weight (g)

Clearance Rate 

Kreeger et al. 2013

Freshwater mussels in tidal Delaware River

Alewife Floaters

24

Investment in Mussel Hatchery

• Produces 500,000 seed per year• Seed are stocked into impaired streams• Survival ~90%, lifespan >30 years, normal growth• Cost is $400,000 per year (once operational)

See poster by Kurt Cheng

Alewife Floaters

25

Predicted Outcomes: Seston Filtration

~1,000 tons per year by Yr 16 

Year2 4 6 8 10 12 14 16TS

S Fi

ltrat

ion

(tons

per

yea

r)

0

200

400

600

800

1000

Stream seeding starts

Year0 5 10 15 20 25 30

TSS

Filtr

atio

n (c

um. t

ons)

0

5000

10000

15000

20000

25000

30000

Stream seeding starts

>30,000 tons TSS by Yr 30

TSS TSS

Alewife Floaters

26

Predicted Outcomes: Nitrogen Filtration

~78,000 lbs/yr by Year 30  >870,000 total lbs by Year 30

Year0 5 10 15 20 25 30pN

Filt

ratio

n (c

um. p

ound

s)0

200000

400000

600000

800000

Stream seeding starts

Year0 5 10 15 20 25 30pN

Filt

ratio

n (p

ound

s/ye

ar)

0

20000

40000

60000

80000

Stream seeding starts

pN pN

Alewife Floaters

27

Return on Investment ?

• Healthy mussel bed >400 pounds N per ha/yr

• No established N market in Delaware River Basin

• TSS removal would cost $400 per ton (dry weight)

• Nitrogen removal would cost $14 per pound

• ROI analyses ignore many ecological benefits

Ribbed Mussels

28

A functional dominant of salt marshes

Mussel tissue biomass exceeds 200 kg per hectare

Concentrated along edge

TSS Removal

• 92.6 metric tons per hectare per year

Particulate Nitrogen Removal

• > 1,000 lbs N per hectare per year

Moody et al. In Prep.

Ribbed Mussels

Losing:69,518 mussels per day8.4 mil L/d filtration capacity

Marsh loss in Delaware Estuary

Ribbed Mussels

Living Shorelines with Ribbed Mussels

May 2010 June 2011June 2010

Shell Bags Packed with Mussels

Dual Benefits of Living Shorelines:

• Stem loss of marsh & associated services

• Boost shellfish services along edge

32

ROI?• Healthy mussel bed >1,000 pounds N per ha/yr

• Typical shellfish‐based living shorelines cost $20‐200 per linear foot (assume $100/ft)

• Assume 100 m LS protects 1 ha of marsh

• Preservation of N services costs $31 per pound N

• Edge restoration will lower this price

• ROI analyses ignore many ecological benefits

Ribbed Mussels

Oysters

33

A functional dominant of Delaware Bay

Form large reefs in many areas

Subtidal mainly, some intertidal

Oysters

34

Shellplanting very effective: 25:1 commercial ROI 

Oysters

35

Shellfish Breakwaters also appear very effective:

See poster by Spencer Roberts

Three Case Studies

36

Alewife floaters Anodonta implicata

Ribbed musselsGeukensia demissa

OystersCrassostrea virginica

Pro• Effective• Opportunity• Intercept 

pollutants

• Effective• Opportunity• Dual benefits• Filter bacteria

• Effective• Opportunity• Industry 

support 

Con• Carrying 

capacity?• Low interest• No hatchery

• Low interest• No hatchery 

investment

• Dermo• Policy bans• Industry 

conflicts

Summary

37

• Freshwater and saltwater bivalves filter water similarly•Most populations are in decline and deserve protection• Enhancing all native species can boost water quality• Future Needs:

o Research on the fate of filtered pollutants (gross vs. net)o Research on carrying capacity in changing climateo Studies of habitat suitability & restoration R & Do Support for hatcheries and implementationo Studies of ROI

CTUIR Freshwater Mussel Project

Healthy Bivalves = Healthy Estuaries

Kreeger

Thank You!

39

Danielle KreegerScience Director(302) 655-990, x104 │ DelawareEstuary.org

Connecting people, science, and naturefor a healthy Delaware River and Bay

Bonus Slides

40

Absorption EfficienciesAb

sorp

tion

Effic

ienc

y (%

)

0

2 0

4 0

6 0

8 0

Marg

. falc.

Anod. calif.

Gonid. ang.

Actin. li

g.

n=24

n=20

n=19

n=25

n=85n=17

n=36

Lasmig. c

ost.

Ellip. d

il.

7 Species:  36 – 66%Not much variation among species

Absorption Efficiencies

Food use increases with food quality

34 44 54 64 74 84 940

20

40

60

80

100n=209, 6 species

Seston Organic Content (%)

Abs

orpt

ion

Effic

ienc

y (%

)

Ammonia Excretion versus Nutritional Status

Bivalves likely remineralizemore N in eutrophicestuaries

More work is needed

Bioavailable N in Seston

Mytilus edulis

Kreeger & Langdon 1993