RESTORATION SCALING OF BENTHIC, AQUATIC AND BIRD 

INJURIES TO OYSTER REEF AND MARSH RESTORATION PROJECTS 

April 16, 2002 

prepared by: 

Dr. Deborah French McCay 

Applied Science Associates, Inc. 

Dr. Pete Peterson 

University of North Carolina - Chapel Hill 

Institute of Marine Sciences 

Michael Donlan 

Industrial Economics, Inc.
2 

Introduction

This report describes our approach and results for scaling marsh and oyster reef 

restoration projects to address benthic, aquatic and bird injuries. 

Summary Description of Scaling Approach

Two separate options are presented as potential restoration projects for benthic, aquatic 

and bird injuries: 1) marsh restoration; and 2) creating and seeding an oyster reef sanctuary. Both 

options will directly enhance production of biota relative to the habitat replaced by the 

restoration.1 The biota directly enhanced by the restoration project in turn will enhance 

populations of other biota that reside at higher trophic levels within the local food web. This 

scaling approach seeks to replace the lost biomass (measured in kilograms or similar units) 

caused by the spill with an equivalent biomass, taking into account trophic level differences 

between biota injured by the spill, biota directly restored by the restoration project and predators 

that consume them. 

Losses Requiring Compensation

Losses of birds are presented in Estimate of Total Acute Mortality to Birds Resulting from 

the Chalk Point Oil Spill, Swanson Creek, Maryland prepared by the Wildlife Injury Workgroup 

of the Chalk Point NRDA Council, final report dated May 2001, and Reproductive Success Of 

Osprey (Pandion haliaetus) Nesting In The Vicinity Of The Chalk Point Oil Spill, final report 

dated October 2001. The Trustees are proposing to restore ruddy duck injuries through a 

breeding habitat protection project, and so are not considered in the scaling calculations 

described in this document. The Trustees estimate that 134 other birds (almost exclusively 

waterbirds) were killed by the spill. Finally, the Trustees estimate a foregone production of 17 

osprey fledglings, as described in the osprey reproductive success report.2

Benthic injuries are described in Quantification of Injury to Benthic Resources from the 

Chalk Point Oil Spill on the Patuxent River (Peterson, 2002), final report dated 5 March 2002. 

This report identifies a total biomass loss of 2,256.1 kg (ash free dry weight), comprised of 

1,932.8 kg of bivalve molluscs (mostly Macoma balthica, also Rangia cuneata), 446.9 kg of 

 1

 This scaling approach can also be used to estimate the benefits associated with 

protection of existing, degrading habitat. 

2

 For consistency with the approach used to scale ruddy duck restoration, injuries to 

fledglings are expressed in units of adult-equivalents. We assume an osprey fledgling survival 

rate of 55 percent (Henny and Wight 1969, Spitzer 1980). 
3 

amphipods (primarily Leptocheirus plumulosus) and offset by a spill-related increase of 123.6 kg 

in opportunistic polychaetes (mostly spionids, also capitellids).3

To ensure consistency in restoration scaling calculations, all injuries are expressed in 

Year 2000 units. Those portions of the benthic injury that occur in 2001 and 2002 must be 

discounted back to Year 2000. This issue does not affect the mollusc and polychaete injury 

estimates presented above, as recovery occurred for those species by the end of 2000. However, 

a portion of the amphipod injury occurred in 2001 and 2002. Discounting those amounts back to 

Year 2000 (using a standard discount rate of three percent) results in a total discounted amphipod 

injury of 439.1 kg. Combining this number with the 1932.8 kg of mollusc injury and 123.6 kg 

credit for increased polychaete production results in a discounted net loss of 2,248.3 kg for 

benthic injuries. This estimate is used as the basis for the calculations performed in this 

restoration scaling analysis, and is translated from ash free dry weight to wet weight using 

factors described in later sections of this report. 

Aquatic injuries are as presented in PEPCO Oil Spill of April 7, 2000 in Patuxent River, 

MD: Modeling of the Fates and Acute Biological Effects of the Spilled Oil on the Water Column

(French McCay and Jennings, March 2002). This report identifies a biomass loss of 2,463.8 

kilograms, comprising approximately 18 different species of fish and shellfish. 

Key Oyster Reef Project Estimates/Assumptions

Key oyster reef project parameters are summarized below and described in more detail in 

Appendix A. First, estimation of the quantitative benefits of oyster reef restoration requires 

knowledge of the habitat chosen for the oyster reef restoration project. Specifically, reefs could 

be constructed on either the soft sediments of muddy sand or on shell bottom. Knowing the 

habitat to be used for the restoration is important for calculation of the net enhancement in 

ecosystem services from the restoration because shell bottom and unconsolidated sedimentary 

bottom possess different benthic communities. 

Specific sites have not yet been identified for potential oyster reefs. With respect to site 

selection, Chris Judy of the Maryland Department of Natural Resources (pers. comm.) notes that 

potential sites are likely to be "marginal" bars that once were productive and may still have a 

remnant population on them, but a sparse one. A variety of habitat conditions may exist. These 

sites may have shells only and no oysters. The shell may be scattered on top of the bar or just 

under a layer of silt. Some bars may be "sanded" and covered with a thin layer of sand. Others 

may be covered by a thicker layer of sand. 

Experts, including Chris Judy (pers. comm.) strongly recommend selection of sites with 

some shell bottom, especially in an area like the Patuxent River where the sediments are 

 3

 As discussed in Peterson, 2002, we "credit" only 50 percent (123.6 kg) of the 247.2 kg 

total increase in polychaete production caused by the spill. This is because of the likelihood that 

a substantial fraction of this production of opportunists suffered food limitation, died, and 

decomposed. A well established pattern of succession in marine sediments is early explosion of 

opportunists, especially polychaetes, followed by starvation (e.g., Marsh and Tenore 1990). 
4 

otherwise very soft. A shell bottom provides greater stability so that loss of reef matrix by 

sinking and burial is minimized. Furthermore, a shell bottom is indicative of the presence of an 

historical oyster reef at that site, which implies greater likelihood of successful restoration. For 

these reasons, we assume that oyster reef restoration will occur on shell bottom.4

Restoring oyster reef habitat in the Patuxent River is expected (based on the literature 

reviewed in Peterson 2001) to produce augmentation in four groups of organisms that serve to 

replace lost ecosystem services; oysters, mud crabs, grass shrimp and small crustaceans 

(amphipods, tanaids and isopods). Oyster recruitment in the Patuxent River is historically low 

and sporadic over time. Therefore, the reef must be established by construction of a shell (or 

similar substrate) matrix on stable shell bottom followed by emplacement of a surface veneer of 

seed oysters. Information obtained from Chris Judy (pers. comm.) and other experts suggests that 

a seeding density of 500 oysters per square meter (approximately two million oysters per acre) is 

reasonable for planning purposes. Our scaling calculations are based on this assumed seeding 

density. Note that a square meter of reef cannot physically hold 500 larger oysters. Mortality 

will occur over time, especially in the first year, resulting in much lower densities of larger 

oysters. DNR field studies in the mid 1990’s in various tributaries including the Patuxent River 

showed high first year mortality among hatchery spat, due to predation by blue crabs and the 

flatworm Stylocchus. 

We considered other potential productivity benefits and ecosystem services provided by 

restored oyster reef, but do not include them in our scaling calculation for a variety of reasons. 

With respect to productivity gains for other invertebrates, we recognize that barnacles settle and 

grow on hard substrata, including oysters. However, barnacles are not extensively consumed by 

vertebrates at higher trophic levels, so their contribution as prey is limited. Furthermore, 

barnacles already grow on unaugmented shell bottom, and we were unable to find quantitative 

data that could be used to evaluate potential increases in productivity associated with 

construction of an oyster reef. 

Reef habitat can augment fish production by enhancing recruitment and prey production, 

which together lead to increases in fish biomass. Although our calculations do not explicitly 

include a contribution of enhanced recruitment or enhanced survival through additional reef 

refuges, both processes are implicitly included in our estimation of augmented transfer of energy 

production from enhanced abundances of invertebrate prey organisms on restored reefs to 

predators and scavengers higher up the food chain. Including both fish prey and fish biomass 

gains in our estimates of reef productivity would be double-counting; these gains are not 

independent of each other. Stated another way, our scaling calculations estimate the increased 

quantity of invertebrate prey biomass made available to the food web; reef size is adjusted to 

produce enough prey to restore lost fish, bird or other injured biomass, given assumptions about 

transfer efficiencies between different levels of the food web. 

 4

 Additional shells or similar substrate will be needed at selected sites to build the oyster 

reef. Chris Judy (pers. comm.) suggests that for planning purposes, it is appropriate to assume six 

inches of shells/substrate will need to be laid down at selected sites. 
5 

We also considered quantifying the potential benefits of oyster filtration in reducing 

turbidity and thereby allowing expansion and recovery of SAV habitat. While some benefit of 

this type may occur, related service loss likely occurred but was not specifically quantified as 

part of the benthic injury quantification. Because injuries were measured in terms of lost 

biomass, restoration should be measured in similar terms. In addition, given the general scale of 

benthic losses it is unlikely that impacts to this service would be large. 

Reef-related production of oysters, mud crabs, grass shrimp and small crustaceans 

associated with an initial seeding is summed over five years to estimate total annual augmented 

production for each species. A portion of this biomass is consumed by predators, contributing to 

their growth and survival. Chris Judy (pers. comm.) and other experts indicated that five years is 

a reasonable assumption for restored oyster reefs in the Patuxent River because of mortality from 

sedimentation, low dissolved oxygen, oyster disease, episodes of higher than average fresh water 

inputs and similar factors. The relative importance of particular causes of oyster mortality 

depends on location of the site in the river. For example, Chris Judy (pers. comm.) indicates 

disease is a key factor downriver and fresh water runoff is a key factor upriver. 

As described in more detail in Appendix A, we make the simplifying assumption that the 

relatively small number of oysters alive after five years die at that point in time (thereby 

contributing to biomass available for predators/scavengers at the end of year 5, rather than over 

ensuing years). This method adequately approximates their quantitative contribution to energy 

transfer to predators and scavengers, for several reasons. Most mortality takes place during the 

first five years; available information indicates that on average, less than ten percent of seeded 

oysters would be expected to survive five years. In addition, annual growth slows for oysters that 

are several years old, and any increments in growth would need to be offset by additional 

discounting applied to production from later years. 

Oysters introduced as seed to restored reefs may reproduce and contribute to spat 

settlement in the region. Physical transport of larvae formed from gametes released by oysters 

surviving to adulthood on the restored reefs may settle successfully on shells and other hard 

substrata downstream. However, given the low historic spat setting trends for the Patuxent River, 

and the low salinities that can occur upriver, spat set in the Patuxent River due to the restored 

reefs is likely to be small relative to the productivity gains already included in our scaling 

calculations (C. Judy pers. comm.). 

Based on production data from local researchers, the scientific literature (including Kneib 

1987, Zimmerman et al. 1989, Llanso and Volstad 2000 - see Appendix A for more information) 

and unpublished data from research conducted by Peterson and his associates, species life history 

information and five year productivity duration, we estimate a reef-related increase in production 

of oyster, mud crab, grass shrimp and small crustacean biomass of approximately 365.9 grams of 

(ash free dry weight) per square meter of restored reef. This estimate reflects the net increase in 

biomass associated with oyster reefs compared to shell bottom for the mesohaline conditions that 

exist in the vicinity of the area affected by the spill. 

The 365.9 grams per square meter estimate of biomass production is used to scale oyster 

reef restoration to all non-oyster injuries identified in the previous section of this report. As 

described in Appendix A, it reflects the portion of reef-generated biomass expected to be 
6 

consumed by predators in the foodweb. These species are expected to benefit from the 

restoration project through consumption of prey generated by it. In addition, non-oyster mollusks 

injured by the spill generally were small, soft-shelled species that primarily serve as prey for 

higher trophic level organisms. The production estimate includes full credit for crab, shrimp and 

small crustacean biomass but only 50 percent of the oyster biomass generated by reef restoration. 

We credit less than 100 percent of the oyster biomass because older oysters are relatively well 

protected from predators. Although some may be scavenged by fish and other predators if their 

shells gape after death, oysters that die during times of the year when predators are less active, 

don't gape after death, are killed by events (e.g., low dissolved oxygen or fresh water inflows) 

that also affect predators, and/or are buried by sedimentation events are more likely to 

decompose than directly contribute to the growth of higher level predators in the foodweb. 

The scaling calculations for non-oyster injuries require injured biomass to be categorized 

according to trophic level relative to the oyster reef invertebrates produced, and ecological 

transfer efficiencies between trophic levels to be estimated.5

 Assumptions for these parameters 

are identified in Appendix B. Injured and restored biota from the same trophic level are assumed 

to be 100% equivalent (from a biomass perspective), as they would presumably have similar 

ecological value in the food web. For example, injured crustaceans are restored on a one-for-one 

basis with crustacean biomass generated by the oyster reef, although in some cases the particular 

species of crustacean injured and restored may differ. To generate equivalencies between biota in 

“higher” or “lower” trophic levels, we rely on estimates of the ecological efficiency from prey to 

predator. Values for production of predator per unit production of prey (i.e., ecological 

efficiency) are taken from the ecological literature, as reviewed by French et al. (1996a) and 

summarized below. 

As noted above, we make the simplifying assumption that restored biomass is equivalent to 

injured biomass from the same trophic level, and so scaled on a one to one basis. Thus, for scaling 

purposes, one kilogram of benthic production is required for every kilogram of benthic biomass lost. 

However, we use different "transfer ratios" for scaling to "higher" levels of the food web. The 

ecological efficiency of prey to invertebrate and fish consumers has been estimated to be 10-30% in 

both freshwater and marine environments by a number of authors (e.g., Slobodkin, 1960, 1962; 

Ryther, 1969; Odum, 1971; Steele, 1974; Petersen and Curtis, 1980; Cohen et al., 1982; Jones, 

1984; Sissenwine et al., 1984; Borgman et al., 1984; Mills et al., 1984; Cohen and Grosslein, 1987). 

Therefore, for fish or invertebrates preying on fish or invertebrates, we use the midpoint of this 

range (20%) of transfer efficiency. The implication of this assumption is that five kilograms of 

benthic production from the reef are required for every one kilogram of biomass injury to fish or 

invertebrate predators of these resources. 

For birds and mammals (which are homeotherms, i.e., warm-blooded, and so less efficient) 

the ecological efficiency is much lower, with estimates ranging from 1-5% (McNeill and Lawton, 

1970; Steele, 1974; Whittaker, 1975; Grodzinski and Wunder, 1975). For our scaling purposes, we 

assume 2% efficiency for birds and mammals feeding on fish or invertebrate prey. Thus, 50 

kilograms of prey biomass are needed for every one kilogram of biomass injury to bird/mammal 

 5

 For purposes of this analysis, "trophic" levels are defined based on feeding patterns and 

preferences. 
7 

predators. Bird injuries are translated to biomass (kg) to include them in this trophic level 

scaling. Exhibit B-1 in Appendix B contains a list of the injuries as both numbers and biomass.6

Oyster biomass lost due to the spill is restored on a one-for-one basis with oyster biomass 

created by the reef restoration project. Because the restored reef simultaneously generates live 

oysters (which directly offset oysters killed by the spill) and oyster, grass shrimp, mud crab and 

small crustacean biomass consumed by predators (used to address non-oyster injuries), the 

restored reef must be of sufficient size to meet both objectives. Scaling calculations indicate that 

the area of reef needed to address non-oyster injuries (described in the following section of this 

report) also will be sufficient to address injuries to oysters. 

Scaling Results – Oyster Reef

Appendix B contains calculations of the total acreage of reef needed to restore benthic 

injury, bird injury (without ruddy ducks), and aquatic injuries and combinations of these 

together. The scaling calculations provide the results identified in Exhibit 1 to compensate for 

injuries to all species (except ruddy ducks). 

Exhibit 1 

OYSTER REEF SCALING RESULTS ASSUMING A ONETIME SEEDING IN 2003 

Injury Compensated Area Required (acres) 

Benthic infauna 2.07 

Aquatic (fish and macroinvertebrate 

predators) 

3.21 

Birds (excluding ruddy ducks) 3.45 

Total 8.74 

 

The area required decreases if an additional seeding effort is undertaken five years after 

the initial seeding. Exhibit 2 provides the results if a second seeding in 2008 is performed. The 

results are slightly more than half the single-seeding results (rather than exactly half) because the 

future gains from 2008-2013 need to be discounted (3% annually). 

Exhibit 2 

OYSTER REEF SCALING RESULTS ASSUMING SEEDING 

IN 2003 AND RESEEDING IN 2008 

 6

 As noted previously, it is our understanding that injuries to ruddy ducks will be restored 

through breeding habitat purchase/protection in the Prairie Pothole region. As a result, we do not 

include ruddy duck injury in our calculations for oyster reef and marsh scaling. 
8 

Injury Compensated Area Required (acres) 

Benthic infauna 1.11 

Aquatic (fish and macroinvertebrate 

predators) 

1.73 

Birds (excluding ruddy ducks) 1.85 

Total 4.69 

Marsh Production Estimates

We reviewed available literature to obtain estimates of marsh annual primary and 

secondary (benthic infaunal) production (as g dry weight m2 yr

-1). Exhibit B-2 in Appendix B is 

a summary of that review. We were able to find good estimates of primary production for 

Spartina and Typha marshes. In addition, we identified quantitative information on secondary 

production in Spartina marshes, but were unable to find similar information for Typha marshes.7

Finally, we attempted to find evidence in the literature for a net gain in production by restoring a 

Phragmites marsh to a Spartina or Typha, but as described in Appendix C do not believe 

available data support this scaling approach. 

Key Marsh Project Assumptions

The scaling for saltmarsh injuries by the Wetlands Assessment Subgroup (2001) was 

performed with the following assumptions: 

• 50 year project duration; 

• restoration project completed in 2003; and 

• net gain of 50% of services in 5 years, 75% services in 10 years, 80 % services in 

15 years and beyond. 

For the present scaling analysis we use similar parameters. 

Scaling Results – Marsh Restoration

Scaling results are provided in Appendix B. The Spartina marsh is the most productive 

of the three plant communities considered and the least acreage is required for this habitat type. 

The table below shows area of marsh required for all benthic, aquatic (based on draft injury 

quantification) and bird injuries, with the exception of ruddy ducks. 

 7

 We note that two different species of Spartina marsh were affected by the Chalk Point 

oil spill: Spartina alterniflora and Spartina cynosuroides. Available information was not 

sufficient to develop species specific estimates of productivity for these different types of 

Spartina marsh. 
9 

With respect to scaling for Spartina marsh, if we use primary production (i.e., plant 

biomass) as the measure of marsh productivity our preliminary results indicate that slightly less 

than one acre of restored marsh would be required to compensate for all benthic, bird (except 

ruddy duck) and aquatic injuries. However, if we use secondary production (i.e., 

macroinvertebrate infauna biomass) as the measure of marsh productivity, just over three acres 

are required. 
10 

Exhibit 3 

MARSH SCALING RESULTS 

Habitat Production Trophic 

Level Used in Scaling

Area Required (acres) 

Spartina marsh Primary 0.72

Spartina marsh Secondary 2.46

Typha marsh Primary 1.48

 To avoid double counting, one of these measures needs to be selected as the basis for 

scaling.8

 In our view, for scaling purposes it is more appropriate to use secondary production as 

the measure of productivity. Use of primary production requires an additional set of assumptions 

regarding transfer efficiencies from primary to secondary production. From a trophic level 

perspective, secondary production is "closer" to the injuries we are scaling to (i.e., benthic, 

aquatic and bird injuries) and so is a better starting point for the scaling analysis. Exhibit 4 lists 

the scaling results for Spartina marsh by injury category (using secondary production as the basis 

for scaling). 

Exhibit 4 

SPARTINA SCALING RESULTS BY INJURY CATEGORY 

Injury Compensated Area Required (acres) 

Benthic infauna 0.58 

Fish and macroinvertebrate 

predators (draft) 

0.91 

Birds (excluding ruddy ducks) 0.97 

Total 2.46 

 8

 While we acknowledge that estimates of primary and secondary production have 

uncertainties associated with them, adding them together would clearly result in substantial 

double-counting, for reasons similar to those described in previous sections of this document. 

Furthermore, we are unable to find a conceptual or empirical basis supporting any approach for 

combining these estimates of productivity in some manner. 
11 

APPENDIX A 

Estimate of Productivity Gains Associated with Oyster Reef Restoration in the 

Patuxent River

Knowing the habitat to be used for the restoration is important for calculation of the net 

enhancement in ecosystem services from the restoration because shell bottom and 

unconsolidated sedimentary bottom possess different benthic communities. These pre-existing 

benthic communities will be covered over and replaced by communities on living oyster reefs 

after restoration has been achieved. Specifically, the shelly bottom provides substantial 

protection against predation for infaunal invertebrates (Castagna and Kraueter 1977) and 

therefore possesses higher densities of bivalve molluscs than a muddy sand habitat. Thus, the 

restoration of an oyster reef on shell bottom in the Patuxent River would not be expected to 

enhance abundances of infaunal bivalves, such as Macoma balthica and Rangia cuneata above 

the already enhanced levels on the shell bottom. 

A second challenge in estimating the enhancement of invertebrate production expected 

from restoring an area of oyster reef habitat in the Patuxent River arises from the low salinity of 

the area likely to be chosen. Salinities in a range of 4-6 ppt are adequate to sustain oyster growth 

and survival. Unfortunately, all available data sets that can be used to estimate the enhancement 

of invertebrates associated with restoration of oyster reef habitat come from higher salinity. The 

data sets that contrast invertebrate abundance on oyster reefs as compared to shell bottom come 

from Back Sound (North Carolina) and Galveston Bay (Texas) at salinities of 20-35 ppt. 

Consequently, we are compelled to estimate augmentation of invertebrate abundance 

from oyster reef restoration in the Patuxent River region by using the earlier studies to estimate 

the factor by which abundances of relevant types of benthic invertebrates increase when shell 

bottom is converted to functional oyster reef habitat. We then apply that ratio to the Patuxent 

River, assuming that the factor by which enhancement will be augmented is unaltered by 

changing salinity over this range. In support of this approach, the groups of organisms that are 

present and important to restoring invertebrate prey for higher-level predators are the same under 

both salinity conditions: mud crabs; grass shrimp; and small crustaceans (amphipods, tanaids and 

isopods). Because of the work of Paynter in oyster reef restoration in the lower Patuxent River 

and in the Severn River and the work of the state of Maryland available through George Abbe 

and Chris Judy, excellent data are available with which to estimate the oyster production of these 

reefs. 

Production of Oysters

Production estimates of oysters are based on an initial density of 500 oysters per m2

(average size = 7 mm in length at planting) of reef and expressed as g of ash-free dry weight 

(AFDW) m-2. This density follows the recommendation of Chris Judy, Maryland Department of 

Natural Resources and other experts based upon past results with hatchery seed plantings and 

input from the Maryland Oyster Roundtable Scientific Committee. Mortality rate of oysters 

(Table 1) during the first year of reef life is estimated from data collected by K. Paynter in his 

current oyster reef restoration study in the lower Patuxent River and his past studies in the 
12 

Severn River. In his studies, seed oyster mortality over the first year averaged 65 % (range 50-

80%). Similar first year rates were seen by DNR in hatchery seed studies in the Patuxent River, 

and other rivers, in the mid-1990’s. Mortality rates drop the following years as oysters are larger 

and more able to withstand crabs and flatworms. Rates can increase again, however, if disease 

or fresh water runoff are factors in the later years (Chris Judy, pers. comm.). 

Annual mortality rate (Table 1) for years 2, 3, and 4 (30%) is based on both Paynter’s 

data and consultation with additional Maryland experts (Judy and Abbe, pers. comm.). 

Assuming a practical limit of five years to the life span of oysters in the Patuxent River (D. 

Breitburg and K. Paynter, pers. comm.), we applied a mortality rate of 100% in year 5 to the few 

oysters remaining: thus no oyster lives to its fifth birthday in our production estimation (Table 1). 

Although some oysters may survive in this river beyond their fifth birthday, even up to 8-10 

years of age, our method adequately approximates their quantitative contribution to energy 

transfer to predators and scavengers. That is true because oysters by age 5 achieve only small 

additional annual increments in size: those small production increments are balanced in our 

calculations by that fact that we have already credited their deaths and thus their transfers to 

higher trophic levels at earlier ages and thus have not had to apply the 3% annual discount rate 

for each later year in this computation. 

Our oyster survivorships and calculations of energy production assume that the restored 

oyster reef is closed to oyster harvest. Length-at-age estimates (Table 1) are based on data from 

Paynter for 0-, 1- and 2-yr-old oysters. For years 3-5, length at age is based on Judy and Abbe 

(pers. comm.). For oysters in the 0-yr-old age class, length-at-age measurements (mm) are 

converted (Table 1) to dry tissue weight at age (g) from length-weight relationships of 

Crassostrea virginica in North Carolina waters (Peterson, unpubl. data). For older ages classes, 

length-to-weight conversions are based on data collected from Maryland oysters (Abbe and Judy, 

pers. comm.). Finally, dry tissue weights are then converted to ash-free dry weight (AFDW) by 

subtracting 20% (Table 1), based on data presented in Appendix 1 of Bahr and Lanier (1981). 

Table 1. Mortality rate and length-at-age and weight-at-length values used in oyster production 

calculations. Parameters are estimated based on Paynter (unpub. data), Judy and Abbe (pers. 

comm.). 

Age Mortality 

Ratea

Average length 

(mm) 

Average dry 

weight (g) 

Average ash-freedry-weight (g) 

 0b 7 0.3 0.24 

1 65% 35 0.6 0.48 

2 30% 60 0.8 0.64 

3 30% 80 1.4 1.12 

4 30% 100 2.3 1.84 

5 100% 115 3.1 2.48 a Our convention reports mortality rate for the previous year, ending on the birthday 

b Age 0 refers the date seed oysters are planted on the reef. 

We first calculate the production of oysters associated with the reef. The change in 

average weight, expressed as g AFDW, between successive age classes is equal to the annual 
13 

production (Pi) of an individual surviving through age class i, Pi = Wi – W(i-1). Production of 

oysters for any given year (Py) is then estimated by multiplying Pi by the number of individuals 

surviving to the end of a particular year, Py = Pi · Ni. Py is adjusted for future production in years 

1-5 by a standard annual discount rate (d) of 0.03: Py·1/(1+d)y

. Total production of oysters is then 

estimated by summing the discounted Py for years 1-5. For the initial year, Wi is set to zero, 

rather than the 7-mm size of planting so as to also give production credit for the growth in the 

hatchery before planting in the field. 

In addition, oysters also provide an ecosystem service by transferring energy to higher 

trophic levels through predation and scavenging by crabs and other consumers. Consequently, 

some fraction of the mortality of oysters on the reef should be credited to achieving the 

restoration in the transfer of prey biomass to higher trophic levels. We use data from Powers and 

Grabowski (2002) to estimate the fraction of the annual mortality of 0-year-class oysters on reefs 

that is caused by predation. Their study assayed predation rates only on small seed oysters (8-12 

mm shell length) superglued to oyster shells and placed on oyster reefs. Predation was 

responsible for 50% of the observed mortality in that study. Although there is evidence that 

predation rate decreases as oyster size increases (White and Wilson 1996), some fraction of 

larger oysters that die from causes other than predators gets transferred to higher trophic levels 

through the activity of scavengers. Scavenging does not appear to play a role in the 0-year-class 

oysters because their shells rarely gape open after death and thus access to scavengers is 

inhibited. We assume for all older age classes that 50% of the mortality results in transferring 

energy to higher trophic levels through the joint effects of predators and scavengers. 

To calculate the biomass of energy transfer from oysters to predators/scavengers, we 

multiplied the number of oysters that died in each year by 0.5 to estimate the numbers of oysters 

that were consumed. We then multiplied the estimated numbers of oyster consumed in each year 

by the mid-year AFDW to compute energy transfer to the next higher trophic level. We use this 

mid-year size as a reasonable approximation knowing that deaths occurred at a range of sizes 

throughout the year. Energy transfers that occurred in the first year were not discounted. For 

each subsequent year’s transfer, the biomass transfer was discounted by 3%. 

These calculations result in estimated oyster production for predators of 188.41 grams 

AFDW per square meter over the 5 year expected duration of oysters seeded after construction of 

the reef, as summarized in Exhibit A-1 below. This productivity estimate would increase 

substantially if additional seeding efforts were implemented in subsequent years. 

Production of Other Biomass

Elevated densities of some important non-oyster biota are expected to occur as a result of 

the conversion of shell bottom habitat to a fully functional oyster reef. To estimate the 

augmented production of these groups, we used a similar approach as in Peterson et al. (2002). 

In that study a contrast between restored oyster reef and unstructured sand/mud bottom was used 

to estimate the quantitative augmentation of fish and mobile crustacean density resulting from 

the restoration of a unit area of oyster reef. The proposed restoration for the Chalk Point injury 

requires an analogous contrast between shell bottom and a fully functional oyster reef in a 
14 

mesohaline system. For benthic infaunal species, density enhancement is unlikely to result 

because the shell bottom already provides adequate refuge and surface feeding area (e.g., 

Skilleter 1994). The types of species groups most likely to show enhancements and of value as 

prey for higher trophic levels are mobile epifaunal species such as grass shrimp, mud crabs and 

small crustaceans (amphipods, tanaids and isopods). All of these are superb fish food, such that 

their complete production can be assumed to be consumed by higher trophic levels. 

Because grass shrimps and mud crabs are considered annual species, we calculated 

annual production by multiplying average weight per individual by the augmented density 

estimate. Consistent with the method of quantification of injury to subtidal benthos following 

the Chalk Point oil spill (Peterson 2002), we assumed that the small crustaceans undergo two 

generations per year. To determine the expected augmentation of absolute abundance per m2

 for 

each prey type deemed to be enhanced by oyster reef presence (grass shrimp, mud crabs, and 

small crustaceans), we subtracted our density estimate of each group on shell bottom (subtracting 

30% from our on-reef density estimate based on data in Powers and Grabowski [unpub. data]). 

The rationale was that the density of crabs, shrimp, and small crustaceans on shell bottom 

represents prey that would be present in the absence of restoring live reef habitat and that the reef 

should be credited only for the enhancement of prey. 

On-reef density estimates of grass shrimp and mud crabs are estimated from those studies 

reviewed in Peterson et al. (2002) that used sampling gear appropriate for the estimation of 

mobile crustaceans (i.e., lift nets, drop samplers) plus additional information from ongoing 

studies in North Carolina (Powers and Grabowski, unpub. data). For grass shrimp we sum the 

density estimates of the spring/summer and fall/winter samplings to account for the likely 

presence of two seasonally recruiting cohorts of grass shrimp within the year (Kneib 1987). For 

mud crabs, that generally have only a single cohort each year, we treated seasonal variation in 

density estimates differently. The spring/summer density of crabs is treated as the estimate of 

maximum recruitment, whereas the fall/winter estimate represents those recruits that have 

survived. 

Because predators will consume almost all mud crabs, we credited the entire augmented 

density (i.e., the density from spring/summer) as prey, but used the differences in seasonal 

abundance to determine the average weight these crabs would likely have achieved before being 

consumed. For crabs consumed after spring/summer but before fall/winter (i.e., density in 

spring/summer – density in fall/winter = crabs consumed during summer), we calculate 

production by multiplying this density difference by the average weight of a mud crab 18 mm in 

carapace width. For that fraction of crabs consumed after the fall/winter sampling (i.e., density 

in fall/winter = crabs consumed after summer’s end), we calculate production by multiplying this 

density estimate by the average AFDW of a mud crab 28 mm in carapace width. Production of 

mud crabs as prey is then the sum of these two seasonal production estimates. 
15 

Exhibit A-1

A. Suspension feeding production

PARAMETERS

 

Age class (i)a

N 

( oyster m-2)b

Average shell 

length at i 

(mm)c

Average tissue 

weight (g, dry 

weight) for id

Average tissue 

weight (g, AFDW) 

for i e W(i

0 500 7 1 175 35 0.6 0.48 02 123 60 0.8 0.64 03 86 80 1.4 1.12 04 60 100 2.3 1.84 05 42 115 3.1 2.48 0

Total production (g m-2) 0 

B. Oyster production to predators

 

Age class (i)a

N 

( oyster m-2)b

Mortality 

during the yr ( 

oyster m-2)

Mortality due 

to predatorsj

Average shell 

length at i 

(mm)c

Average tissue 

weight (g, dry 

weight) for id

Average tissue 

weight (g, AFDW) 

for i e

Mid-year weight 

(g AFDW for i) k

Mi

we

AFD

0 500 325 163 7 0.3 0.24 0.36 1 175 53 26 35 0.6 0.48 0.56 2 123 37 18 60 0.8 0.64 0.88 3 86 26 13 80 1.4 1.12 1.48 4 60 18 9 100 2.3 1.84 2.16 5 42 42 21 115 3.1 2.48 2.76 

a Age class notation: age class 1 is 365 days past original planting day (i.e. age 0).b Mortality rate is 65% during first year and 30% for all following years based on Paynter (unpubl. data, pers comm.) and Abbe and Judy (pers. comm.). O

 All oysters are assumed to be dead after reaching their 5th birthday (see report text for explanation).

c Age-length relationships for oysters through age 2 are based on Paynter (unpubl. data, pers. comm.) with growth slowing in years 3-5 (based on Judy and Length-weight relationship based on Paynter (unpubl. data) for age class 0 and Abbe and Judy (pers. comm.)for all other age classes.e Based on data presented in Bahr & Lanier 1981 ash free dry weight (AFDW in g) is calculated as 0.8 of dry tissue weight (g).f Production is calculated as g AFDW without oyster shell to match the methodology used in the injury quantification.g Change in weight from one year class to the next is calculate by subtracting the previous year's weight gain from the current year's estimate.h Production is calculate by multiplying the average weight gain of an individual by the total number individuals surviving at the end of that particular year.i Production is discounted at a rate of 0.03 yr-1 from the time restoration is completed.j We assume 50% of oysters mortality is transferred to predators/scavengers.k Predation credit for oysters during the year is based on the average weight for that year (weight at the end of previous age class+weight at the end of curL Production going to predators/scavengers is calculate by multiplying mortality due to predators by the mid-year weight estimate. 
16 

Length estimates were based on data in Kneib (1987) for grass shrimp or from ongoing 

studies in North Carolina for mud crabs (Powers and Grabowski, unpub. data). Dry tissue 

weights of mud crabs and grass shrimp were determined from live and archived individuals at 

the Institute of Marine Sciences, University of North Carolina. Expected AFDW for mud crabs 

and grass shrimp were calculated by subtracting 14% from the dry tissue weight. 

On-reef density estimates of the small crustaceans (amphipods, tanaids, and isopods) are 

estimated from quantitative density data on oyster reefs in Zimmerman et al. (1989). Their study 

used coring on oyster reefs in Galveston Bay (Texas) to document invertebrate density in two 

seasons, sampling in July and December. Consistent with the methods used in Peterson (2002) 

to compute the injury to amphipods, we assumed that each of these small crustaceans undergoes 

two generations annually and that the Zimmerman et al. (1989) samplings correspond to the peak 

abundances of each cohort. Consequently, we added the abundances of these two cohorts and 

multiplied by average AFDW per individual (from Patuxent River data in Llanso and Volstad 

2000) to form our estimate of the total annual production. This calculation was done separately 

for amphipods, tanaids, and isopods but reported as the sum here in the text. The AFDW value 

used for each of these three taxa of small crustaceans represents the unweighted average 

computed across all species within the relevant taxon found in the Llanso and Volstad sampling 

of subtidal benthos in the Chalk Point area of the Patuxent River. Because it is likely that all of 

this production will be consumed by fish and other predators, we credit the entire annual 

production of small crustaceans as prey. 

Production for grass shrimp, crabs and small crustaceans in years after year 1 was 

discounted by a standard annual discount rate (d) of 0.03: Py·1/(1+d)y

. We then summed these 

production estimates over the five-year lifetime of a functional oyster reef to produce an estimate 

of total annual augmented production for each taxon. Chris Judy and other experts report that for 

scaling purposes, oysters on restored reefs in the Patuxent River can be expected to be productive 

for five years after an initial seeding because of mortality from sedimentation, low dissolved 

oxygen, oyster disease and similar factors. 

These calculations result in estimated oyster reef production of 82 grams (AFDW) of 

mud crabs, 83 grams (AFDW) of grass shrimp and 12 grams (AFDW) of small crustaceans per 

square meter over the five year expected duration, as summarized in Exhibit A-2 below. 
17 

Exhibit A-2

C. Production of other prey species (grass shrimp & mud crabs)

 1. Mud Crabs

Seasona

Augmented 

Density 

(No. m-2)

 b

Reef Enhanced 

Density 

(No. m-2) c

N preyed 

upon 

d

Average 

carapace 

width at age i 

Average 

Weight (g, 

wet)

Average 

Weight (g, dry 

tissue)

Average 

weight (g, 

AFDW)

AFDW P 

= N*W

Spring/Summer 66 46.2 34.3 1.8 0.81 0.24 0.21 7.20

Fall/Winter 17 11.9 11.9 2.8 3.50 1.05 0.90 10.74

Year Total 17.94

Year 

Annual Crab P ( 

AFDW)

Dicounted 

Crab P 

(AFDW)

e

1 17.94 17.42

2 17.94 16.91

3 17.94 16.42

4 17.94 15.94

5 17.94 15.48

Total Production (g m

-2) 82.17

 2. Grass shrimp

Seasona

Augmented 

Density 

(No. m-2)

 b

Reef Enhanced 

Density 

(No. m-2) c

N preyed 

upon 

d

Average 

carapace 

width at age i 

Average 

Weight (g, 

wet)

Average 

Weight (g, dry 

tissue)

Average 

weight (g, 

AFDW)

AFDW P 

= N*W

Spring/Summer 151 105.7 105.7 29 0.3 0.1 0.09 9.09

Fall/Winter 151 105.7 105.7 29 0.3 0.1 0.09 9.09

Year Total 18.18

Year 

Grass shrimp 

P (AFDW)

Discounted Grass 

shrimp P (g, 

AFDW)

1 18.18 17.65

2 18.18 17.14

3 18.18 16.64

4 18.18 16.15

5 18.18 15.68

Total Production (g m

-2) 83.26

a

 Season density was measured.

b

 Augmented density (density on oyster reef - density on unstructured bottom). c

 Enhanced density on reefs (density on live oyster reef - density on shell bottom). d

 Number of individuals from the season that are consumed by predators. e

 Production is discounted by 0.03 yr

-1

.
18 

Exhibit A-2 (continued)

3. Small Crustaceans, amphipods+tanaids+isopods

Taxaa

Augmented 

Density 

(No. m-2)

 b

Reef Enhanced 

Density 

(No. m-2) c

Avg. 

individual 

weight (g, 

AFDW)

d

Biomass 

(g/m2)

# of 

generations/

year

Annual 

Production 

(g/m2)

Amphipods 8320 5824 0.00019 1.10656 2 2.21312

Tanaids 2061 1442.7 0.00005 0.072135 2 0.14427

Isopods 422 295.4 0.00045 0.13293 2 0.26586

Total small crustaceans 2.62325

Year 

Annual 

production

Discounted Annual 

Production

1 2.62 2.55

2 2.62 2.47

3 2.62 2.40

4 2.62 2.33

5 2.62 2.26

Total Production (g m

-2) 12.01

a

 Taxa = amphipods, tanaids, or isopods

b

 Augmented density (density on oyster reef - density on unstructured bottom);

 density estimates are from Zimmerman et al. 1989

c

 Enhanced density on reefs (density on live oyster reef - density on shell bottom). d

 Average weights are identical to those used in injury calculations. 

 The weights for each group represent the average of species collected

 in the assessment. For tanaids, the average weight for a corophid was used.

e

 Production is discounted by 0.03 yr

-1.
19 

APPENDIX B 

Scaling Estimates for Compensatory Restoration 

The scale (area) of habitat needed to compensate for the injuries resulting from the Chalk Point spill are 

calculated using the following assumptions: 

• The bird injury is as from: “Estimate of Total Acute Mortality to Birds Resulting from the Chalk 

Point Oil Spill, Swanson Creek, Maryland, April 7 2000”, prepared by the Wildlife Injury 

Workgroup of the Chalk Point NRDA Council, dated May 2001 and “Reproductive Success Of 

Osprey (Pandion haliaetus) Nesting In The Vicinity Of The Chalk Point Oil Spill”, Final Report 

October, 2001. Scaling for ruddy ducks is calculated separately and not included in the totals. 

• The benthic infauna and mollusk injury is from Peterson (2002). Half of the net gain in 

polychaete production is credited against the amphipod injury to calculate a total benthic infauna 

injury (following the arguments in Peterson, 2002). The injuries are translated to wet weight from 

ash free dry weight (AFDW) assuming AFDW is 86% of (decalcified) dry weight and dry weight 

is 15% of wet weight. 

• The fish and macroinvertebrate injury is from French McCay and Jennings (March 2002). Scaling 

to oyster reef and marshes is performed for all injuries except for oysters in Exhibits B-3 to B-7. 

• All marsh restoration projects are assumed habitat creation projects, where the previous habitat for 

the restored area is assumed to have no contribution to fauna equivalent to those injured. 

• Scaling is calculated assuming that the fauna supported by the restored habitat are food-limited, 

such that the net gain in production from the habitat translates to a net gain is consumer species. 

• A net gain is species of the same trophic level is assumed to be equivalent in ecological services to 

the injured species. 

• Ecological efficiencies (given in Exhibits B-3 to B-7) are calculated relative to benthic infaunal 

detritivores and omnivores using the assumed ecological efficiencies per step in the food chain in 

the table below. When macrophyte production is used for scaling, the ecological efficiency 

relative to detritivores is multiplied by 0.04 to account for the additional trophic transfer step from 

macrophyte production to detritivore. If an injured resource is of the same trophic level as 

detritivores, the ecological efficiency is indicated as 100% in Exhibits B-3 to B-7 (i.e., they are 

assumed equivalent in value). 

Assumed ecological efficiencies for trophic step: 

Consumer Prey/food % Efficiency 

Invertebrate or fish Invertebrate 20 

Birds, mammals Invertebrate 2 

Invertebrate or fish Finfish 20 

Birds, mammals Finfish 2 

Invertebrate detritivore Macrophytes 4 

Finfish detritivore Macrophytes 4 

Birds, mammals (herbivores) Macrophytes 0.03 

• The project life is assumed 50 years for marshes, and 5 or 10 years for oyster reef. 

• For the oyster reef, production available to the food web for each of the 5 years following a single 

year of seeding is assumed 365.9 g AFDW/m2

 as described in Appendix A, corrected to wet 

weight using available species-specific information in Exhibits A-1 and A-2. Absent speciesspecific information, we assume AFDW is 86% of dry weight, and dry weight is 15% of weight. 

Two options are scaled: a single seeding in 2003 and two seedings of the same acreage, one in 

2003 and one in 2008. The second seeding is discounted for 8 years of lag time between the 

injury and restoration. 

• Oysters are assumed restored by oyster reef suspension feeding production of 199.3 g AFDW/m2

(Appendix A). Assuming a conversion for oysters of 80% AFDW per unit dry weight and 15% 
20 

dry weight of wet weight, this is equivalent to 1661 g wet weight/m2 (these same conversion 

factors are used to translate the oyster injury). Results are in Exhibit B-8. As noted in the text, 

these services are provided simultaneously with predation services; the calculations in Exhibit B-8 

demonstrate that the size of reef needed to scale non-oyster injuries also will provide sufficient 

oyster biomass to restore oyster injuries. 

• For marshes, it is assumed that the marsh develops to 80% functionality in 15 years and levels off 

to remain at that level indefinitely. This is based on Wetlands Assessment Subgroup (2002) in 

their scaling of the Chalk Point marsh restoration and is consistent with French et al (1996, based 

on Dunn and Best, 1983; Broome et al, 1986; D’Avanzo et al, 1989; PERL, 1990; Blair, 1991). 

The logistic model in French et al (1996) is used to make these calculations, such that the gains 

increase according to that function over years after the restoration is initiated. 

• Future gains from marsh production are discounted at 3% annually. 

• It is assumed that the restoration projects are performed in 2003. Discounting is used to account 

for the lag from the year of the spill (2000) to 2003. 
21 

Exhibit B-1. Bird injury as numbers (from the Wildlife Injury Working Group) and biomass (kg). 

Estimated weight per bird is from Sibley (2000). 

Affected Biota* Numbers Lost kg/bird kg Injury 

Greater Scaup 9 1.05 9.45 

Green-winged Teal 11 0.35 3.85 

Canada Goose 3 3.05 9.15 

Mallard 19 1.1 20.9 

American Coot 34 0.65 22.1 

Total waterfowl 76 65.45 

 

Double-crested Cormorant 43 1.7 73.1 

Loon 1 4.1 4.1 

Gulls 2 1.1 2.2 

Terns 2 0.16 0.32 

Total seabirds 48 79.72 

 

Great Blue Heron 3 2.4 7.2 

Virginia Rail 1 0.085 0.085 

Total waders 4 7.285 

 

Osprey (Adults) 2 1.6 3.2 

Osprey (Fledglings)** 8 1.6 12.8 

Kingfisher 1 0.15 0.15 

Total aerial piscivores 11 16.2 

 

Other (passerine+unident.) 3 0.01 0.03 

* The Trustees propose to restore ruddy duck injuries through a breeding habitat protection project, and so 

ruddy duck injuries are not scaled using the method described in this document. 

** For consistency with the approach used to scale ruddy duck restoration, injuries to osprey fledglings (17 

fledglings lost) are converted to adult-equivalents (8 adult-equivalents lost) before performing scaling 

calculations. We assume an osprey fledgling survival rate of 55 percent (Henny and Wight 1969, Spitzer 

1980). 
22 

Exhibit B-2. References for biomass, density or production that were reviewed Component References Details Production 

Macrophytes Valiela, I., Cole, M. L. , McClelland, J., Hauxwell, J., 

Cebrian, J., Joye, S. B (2000) Role of salt marshes as part of coastal landscapes.pp.23-38. See p.30 Fig 2. In Weinsteen & Kreeger (2000) * 

Production of macroalgae, eelgrass and phytoplantkton are functions of the ratio of the saltmarsh area to estuary areaWaiquot Bay estuaries 

Ranges for saltmarsh to macroalgae eelgrass 0does not staproduction 

Macrophytes Chambers, R. M., Meyerson, L. A. & Saltonstall, K. (1999) 

Expansion of Phragmites australis into tidal wetlands of 

North America. Aquatic Botany, Vol. 64. Pp. 261-273 

Review of causes and effects of Phragmites expansion into tidal wetlands. Evidence that Phragmitesdominated brackish wetlands with full tidal flows can provide strong trophic link to fishes and invertebrates of estuaries. However, evidence that Phragmitescan, in some instances, cause small creeks to fill in restricting passage of foraging fish/crustaceans. However, this result is not consistent. 

No quantita

Macrophytes Daie & Waigert (1996) cited in Newell S. Y., & Porter D. 

Microbial secondary production from salt marsh-grass shoots, and it’s known and potential fates. Pp 159-185. See p. 168 in Weinsteen & Kreeger (2000) * 

Estimated for annual production of Spartina shoots at Sapelo Average for tall/short forms 

1313 g m-2 
23 

Macrophytes Keefe, W. Marsh production: a summary of the literature. 

Contributions in Marine Science. Vol 16, 1972 

Summary of reported biomass and production figures to that date. Gives values broken down by species and locale. Have indicated here results from locales closest to PEPCO site only Other species/locales listed also Aerial v below ground data are reported for some species/locales 

Aerial ProdSpartina altPhragmites Island) S. patens 99Juncus roemScirpus ameTypha latifoT. angustifoTypha spp. Carex strictBiomass (g Spartina alt300 (New J

Macrophytes Roman, C. T. & Daiber, F. C. (1984) Aboveground and 

belowground primary production dynamics of two Delaware Bay tidal marshes. Bulletin of the Torey Botanical Club. Vol. III, No. 1: 34-41. 

Compares aboveground and below ground estimates of production among Spartina (different forms) and Phragmites. Delaware Bay Brackish tidal marshes. Mean annual salinity of creek = 10-15ppt 

Net annual production g dry wt m-S. alternifloS. alternifloS. patens Distichlis spPhragmites Net annual bproduction g dry wt m-S. alternifloS. alternifloS. patens Phragmites 
24 

Macrophytes Stribling, J. M. & Cornwell, J. C. (1997) Identification of 

important primary producers in a Chesapeake Bay Tribal Creek System using stable isotopes of carbon and sulphur. Estuaries. Vol. 20, No. 1. pp.77-85. 

Reports biomass at midcreek (2-12ppt) and uppermost point (0-4ppt) for macrophytes Also has C and S content of macrophytes and consumers 

S. alterniflo

Macrophytes Windham, L. (2001) Comparison of biomass production 

and decomposition between Phragmites australis (common red) and Spartina patens (salt hay grass) in brackish tidal 

marshes of New Jersey, USA. Wetlands. Vol. 21, No. 2: 179-188. 

Compared standing stock (above/below ground) and rates of decay between marsh types Brackish section of Mullica River, Great Bay, southern New Jersey 0.5 to 18 ppt P. australis invasion leads to build up of organic biomass in sediment compared to S.patens

Peak-season (mean ash f

S. patens P. australi

Peak season (mean ash f

S. patens 

P. australi

Total pool dfree dry wei

S. patens 

P. australi

Macrophytes Windham, L. & Lathrop, R. G. (1999) Effects of 

Phragmites australis (Common Reed) invasion on aboveground biomass and soil properties in brackish tidal marsh of the Mullica River, New Jersey. Estuaries. Vol. 22, No. 4 pp.927-935. 

Compared soil characteristics with age of invasive Phragmites stands Brackish region (0.5-18 ppt) about 17 km upstream from river mouth 

Biomass (g  “mixed sho

Phragmite

Phragmites function of 
25 

Birds Benoit, L. K. & Askins, R. A (1999). Impact of the spread 

of Phragmites on the distribution of birds in Connecticut tidal marshes. Wetlands, Vol. 19, No. 1. pp. 194-208. 

Compares bird counts for individual spp. among 6 vegetation types: Salt and brackish marshes 1.Short-grass meadow (>50% mixed cover) 2. Phragmites (> 50% monoculture cover) 3. Cattail (>30% cattail, < 30% other spp.) 4. Brackish mixture (graminoids and tall emergents, each < 50% cover). 5. Short Spartina alterniflora (>50% cover < 50 cm tall) Abundance of individual spp. also compared 

Highest meano. of marsh Brackish miPer 7,854 mFor comparPhragmitesShort SpartSpecies usinCattail: 8 PhragmitesShort SpartBrackish miShort-grass 

Fish/Decapods Smith, K. J., Taghon, G. L. & Able K. W. Trophic linkages 

in marshes: Ontogenetic changes in diet for young of the year Mummichog, Fundulus heteroclitus. Pp. 221-236 in 

Weinsteen & Kreeger (2000) * 

YOY sampled from flooded salt marsh surfaces, lower Delaware Bay Former salt hay farm, now extensive stands of Spartina alterniflora

Density was F. heterocliproduction 
26 

Fish/Decapods Cicchetti, G. & Diaz, R.J. Types of saltmarsh edge and 

export of trophic energy from marshes to deeper habitats. Pp. 515 in Weinsteen & Kreeger (2000) * 

Estimated density and biomass of fish and crabs over 4 marsh habitats (lower York River, Chesapeake Bay, NY) Marshes were narrow fringing edges of a small embayment. Marsh was tall and long form Spartina alterniflora at edges grading into S. patens/Distichlis spicata at interior 

Biomass (g  (density (inSand edge  Fundulid Palaemon Transient Blue crabMarsh edge  Fundulid Palaemon Transient Blue crabWithin 3m o Fundulid Palaemon Transient Blue crabMarsh inter

Fundulid

 Palaemon Transient Blue crab

Fish/Decapods Weinstein, M. P. & Balletto H. H. (1999) Does the 

common reed, Phragmites australis, affect essential fish 

habitat? Estuaries. Vol. 22. No. 3B: 793-802. 

Literature review. Argues that negative impact of Phragmites invasion for fish/decapods is through building up of soil profile (reducing tidal exchange) and reduction of edge to marsh area. 

No quantitaindicates imfactors 
27 

Fish/Decapod Able, K. W. & Hagan, S.M. (2000) Effects of Common 

Reed (Phragmites australis) invasion on marsh surface 

macrofauna: Response of fishes and decapod crustaceans. Estuaries. Vol. 23: 633-646 

 Compare larval, juvenile and later stages of fish/crustacean abundance and species richness among marshes were P. australis or S. alterniflora + 

other spp. were aerial dominants. All sites within 1.5 km2 area. 

Mullica River, southern New Jersey. Salinity 0-20 ppt Elevation not significantly different between sites. Marsh surface topography DID vary by vegetation type. Standing water present at Spartina sites, little or none at Phragmites sites. Larval fish consistently far more abundant in S. alterniflora than in P. 

australis.Larval fish also more abundant at back of S. alterniflora than front edge. Note: larval fish were collected in pit-traps that mimicked standing pools of water.No strong and consistent pattern for later stages. Overall fish abundance similar. Some species most abundant in Spartina, some in Phragmites. 

Pit traps –seCPUE (catcconsecutive All fish spe P. austral

 S. alternifAll crab spe P. australi S. alternifFlume nets CPUE (catcAll fish spe P. austral S. alternifAll crab spe P. australi

 S. alternifF. heteroclialmost excu(with pools) (lacking pooAs F. hetero

eggs, pattern the strongly larvae contithen occupy preference a
28 

Fish/Decapods Meyer, D. L, Johnson, J. M., Gill, J. W. (2001) Comparison 

of nekton use of Phragmites australis and Spartina 

alterniflora marshes in the Chesapeake Bay, USA. Marine 

Ecology Progress Series. Vol 209: 71-84 

Compare fish/crustacean abundance and spp. richness among marshes of each type. Note: sites for both types were structurally similar: relatively open with small sinuous channels between hummocks. See Weinstein & Balletto Salinity 5-10 ppt No significant (or consistent)difference in abundance or biomass of any species or all spp. of fish Paper also reports densities of spp. at Table 3. 

Mean bioma[& decapod g wet wt. peMay 

PhragmiteSpartina 

July 

PhragmiteSpartina 

October 

PhragmiteSpartina 

. 

Fish/Decapod Able, K. W., Nemerson, D. M., Light, P. R. & Bush, R.O 

(2000) Initial response of fishes to marsh restoration at a former salt hay farm bordering Delaware Bay. Pp. 749-773. in Weinsteen & Kreeger (2000) * 

Compared nekton between salt-hay farm ditches and creeks where hydroperiod had been restored 

recently and 2 decades previously. Delaware Bay Salinity in recently & longer term restored creeks similar: 12-22 ppt. 

Large increarestoration. Species richPre: 2 spp Abundance change was different ge

Fish/Decapod Kneib, R. T. (2000). Salt marsh ecoscapes and production 

transfers by estuarine nekton in the southeastern Unites States. Pp. 267- 291. in Weinsteen & Kreeger (2000) * 

Reviews evidence for nekton production from tidal marshes (at general “marsh” level) and quotes production values reported in the literature. 

Fundulus he10-16 g dry 1977) Palaemonne9-16 g dry wWelsh 1975
29 

Fish Hettler W. F Jr. (1989) Nekton use of regularly-flooded 

saltmarsh cordgrass habitat in North Carolina, USA. Marine Ecology Progress Series. Vol. 56: 111-118. 

Sampled fish and crustaceans from a regularly-flooded saltmarsh monthly. Compared abundance and biomass by stream order and month Salinity 25-35 ppt 

Reports bioeach specieIndividual sfor rivulets Mean biomacombined pg per 10 m o

Fish Meredith, W. H. & Lotrich V. A. (1979) Production 

dynamics of a tidal creek population of Fundulus heteroclidus (Linnaeus). Estuarine and Coastal Marine Science. Vol. 8: 99-118. 

Calculated biomass and production for life-stages of Fundulus heteroclitus From main channel of a creek off Delaware Bay. Salinity 18-28ppt 

Reports proclass (and suAverage ann40.7 g dry w

Macroinfauna Sarda, R. Foreman, K. and I. Valielea. (1995) 

Macroinfauna of a southern New England salt marsh: seasonal dynamics and production. Marine Biology Vol. 121: 431-445 

Compared density and biomass between sandy inorganic, sandy organic and muddy sediments Great Sippewisset salt marsh (Mass.) Salt marsh dominated by Spartina spp. Mean salinity 26 ppt Also reports seasonal values for individual spp. 

Production 

 Sandy ino Sandy org Mud Biomass (g  Sandy ino Sandy org Mud Density (ind  Sandy ino Sandy org Mud 
30 

Macroinfauna Sarda, R. Valiela, I. & Foreman K. (1995) Life cycle, 

demography, and production of Marenzelleria viridis in a salt marsh of southern New England. J. mar. biol. Ass. U.K. Vol. 75: 725-738 

Reports density and biomass of M.viridis and all other macroinfaunal spp. from sandy organic sediments Gives results by month also Great Sippewissett marsh (Mass.) Mean salinity 26 ppt 

Annual prod

60 g m-2 yr2 yr-1 in subM. viridis  Ann. Mean  Ann. Mean All other sp Ann. Mean  Ann. Mean 

Macroinfauna Fleeger, J. W. & Palmer, M. (1982) Secondary production 

of the estuarine, meiobenthic copepod Microarthridion littorale. Marine Ecology Progress Series. Vol 7. 157-162 

Annual production estimate for one meiobenthic sp. Soft sediment between “healthy” Spartina culms Intertidal estuary 

0.14 g (dry) 

Macroinfauna Sarda, R. Foreman, K. Wermee, C. E., and Valiela, I. 

(1998) The impact of epifaunal predation on the structure of macroinfaunal invertebrate communities of tidal saltmarsh Creeks. Estuarine, Coastal and Shelf Science. Vol. 46: 657-669. 

Reports annual production of macro-infauna in sandy organic sediments Great Sippewissett marsh (Mass.) Paired sites along a salinity gradient. Mean range 3.6 to 20 ppt 

Average promacroinfaun 77.2 g dry Values are aspp. 
31 

Macroinfauna & Fish 

Fell, P. E. Weissbach, S. P., Jones D. A. Fallon M. A., Julie A. Z., Faison E. K., Lennon K. A., Newberry K. J. & Reddington L. K. (1998) Does invasion of oligohaline tidal marshes by red grass, Phragmites australis (Cav.) Trin. ex Steud., affect the availability of prey resources for the mummichog, Fundulus heteroclitus L.? Journal of Exp. 

Mar. Biol. Ecol. 222:59-77. 

Compared macroinfaunal abundance and feeding by F. heteroclitus on macroinfauna among Phragmitesmonocultures and mixed stands (Juncus/Spartina) 

Connecticut River Paired sites along a salinity gradient. Mean range 3.6 to 20 ppt Four major macroinfaunal spp. were at least, and often more, abundant in Phragmites. monoculture stands than adjacent mixed stands. F. heteroclitus fed effectively within the Phragmites monoculture –using both the marsh surface (when flooded) and channels through the marsh. Gut contents of F. heteroclitus that had fed in the two marsh tyes weer similar 

Mean dens

reported fofor the two Abundancdifferent. 

Phytoplankton Valiela, I., Cole, M. L. , McClelland, J., Hauxwell, J., 

Cebrian, J., Joye, S. B (2000) Role of salt marshes as part of coastal landscapes.pp.23-38. See p. 30 Fig 2. In Weinsteen & Kreeger (2000) * 

Production of macroalgae, eelgrass and phytoplantkton are functions of ratio of saltmarsh to estuary area (Waiquot Bay estuaries) 

Ranges for of saltmarsPhytoplank

(linear) does not st
32 

Bacterial production 

Newell S. Y., & Porter D. Microbial secondary production from salt marsh-grass shoots, and it’s known and potential fates. Pp 159-185. See p. 169. Table 3. in Weinsteen & Kreeger (2000) * 

Study reports estimates for: -Bacterial productivity on dead Spartina shoots -Bacterioplankton -Bacteria in sediment (to 20 cm) -Total fungal productivity 

10 (summe528(summ750 (summ369 (summrates are p

Bacterial production 

Sullivan M. J., & Currin C, A. Community structure and functional dynamics of benthic microalgae in salt marshes. Pp.81-106. See Table 2. p.93 in Weinsteen & Kreeger (2000) * 

Annual benthic microalgal productivity in Saltmarshes compared geographically 

MassachusDelaware 

* Concepts and controversies in tidal marsh ecology (2000). Edited by Weinstein, M.P. & Kreeger, D. A.. Kluwer Academic Publisher0-7923-6019-2. 
Exhibit B-3. Restoration scaling of fish, invertebrate and bird injuries using secondary (benthic) production from 

oyster reef available to the food web (365.9 g AFDW/m2

 = 2272 g wet weight/m2), assuming the reef is seeded once 

in 2003. Time for restored habitat to be 99% of fully functional is assumed 1 year and the project life is 5 years. 

Species Category Total 

Injury 

(kg) 

Trophic Level Ecological 

Efficiency 

Relative to 

Benthic 

Detritivores 

(%) 

Compensatory 

Production 

(kg)a

Habitat 

Area 

(m2)b

Habitat 

Area 

(acres) 

Fish and 

Invertebrates: 

 

Small pelagic fish 217 planktivorous 20 1,085 522 0.129 

Large pelagic fish 737 piscivores 4 18,416 8857 2.188 

Demersal fish 802 bottom feeders 20 4,009 1928 0.476 

Demersal 

macroinvertebrates 

 706 bottom feeders 20 3,530 1698 0.419 

Mollusks 14,983 filter/bottom 

feeder 

100 14,983 7206 1.781 

Benthic 

invertebrates (nonmolluscan) 

 2,446 filter/bottom 

feeder 

100 2,446 1177 0.291 

Birds: 

Waterfowl ( # * kg 

each) 

 65 bottom feeders 2 3,273 1574 0.389 

Seabirds ( # * kg 

each) 

 80 piscivores 0.4 19,930 9585 2.368 

Waders ( # * kg 

each) 

 7.2 piscivores 0.4 1,800 866 0.214 

Shorebirds ( # * kg 

each) 

 0.1 bottom feeders 2 4 2 0.001 

Raptors ( # * kg 

each) 

 16 piscivores 0.4 4,038 1942 0.480 

 

Subtotal fish and 

invertebrates 

 19,891 21,386 5.28 

Subtotal birdsc 169 13,968 3.45 

Total all species 20,059 73,512 35,355 8.74 

a: compensatory production = total injury / ecological efficiency. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

b: habitat area = compensatory production / 2.079 kg per square meter. 2.079 kg per square meter = 2.272 kg per 

square meter / (1.03)3

, and is the oyster reef productivity expressed as wet weight, summed over the productive life 

of the project and discounted three years to account for timing differences between injury and expected restoration. 

Calculated totals may vary slightly from numbers presented in the table due to rounding. 

c: as noted in the text, scaling results for bird injuries presented here do not include ruddy ducks. 
34 

Exhibit B-4. Restoration scaling of fish, invertebrate and bird injuries using secondary (benthic) production from 

oyster reef available to the food web (365.9 g AFDW/m2

 = 2272 g wet weight/m2), assuming the reef is seeded once 

in 2003 and reseeded in 2008. Time for restored habitat to be 99% of fully functional is assumed 1 year and the 

project life is 10 years. 

Species Category Total 

Injury 

(kg) 

Trophic Level Ecological 

Efficiency 

Relative to 

Benthic 

Detritivores 

(%) 

Compensatory 

Production 

(kg)a

Habitat 

Area 

(m2)b

Habitat 

Area 

(acres) 

Fish and 

Invertebrates: 

 

Small pelagic fish 217 planktivorous 20 1,085 280 0.069 

Large pelagic fish 737 piscivores 4 18,416 4756 1.175 

Demersal fish 802 bottom feeders 20 4,009 1035 0.256 

Demersal 

macroinvertebrates 

 706 bottom feeders 20 3,530 912 0.225 

Mollusks 14,983 filter/bottom 

feeder 

100 14,983 3870 0.956 

Benthic 

invertebrates (nonmolluscan) 

 2,446 filter/bottom 

feeder 

100 2,446 632 0.156 

Birds: 

Waterfowl ( # * kg 

each) 

 65 bottom feeders 2 3,273 845 0.209 

Seabirds ( # * kg 

each) 

 80 piscivores 0.4 19,930 5147 1.272 

Waders ( # * kg 

each) 

 7.2 piscivores 0.4 1,800 465 0.115 

Shorebirds ( # * kg 

each) 

 0.1 bottom feeders 2 4 1 0.000 

Raptors ( # * kg 

each) 

 16 piscivores 0.4 4,038 1043 0.258 

 

Subtotal fish and 

invertebrates 

 19,891 11,484 2.84 

Subtotal birdsc 169 7,501 1.85 

Total all species 20,059 73,512 18,985 4.69 

a: compensatory production = total injury / ecological efficiency. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

b: habitat area = compensatory production / 3.872 kg per square meter. 3.872 kg per square meter is the oyster reef 

productivity expressed as wet weight, summed over the productive life of the project and discounted to account for 

timing differences between injury and expected restoration. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

c: as noted in the text, scaling results for bird injuries presented here do not include ruddy ducks. 
35 

Exhibit B-5. Restoration scaling of fish, invertebrate and birds injuries using primary (macrophyte) production from 

a Spartina saltmarsh. Saltmarsh production is assumed 6580 g dry wt m-2 yr-1 (from Roman and Daiber, 1984, 

assuming dry weight is 15% of wet weight). Recovery is assumed to reach 80% of this rate in 15 years. 

Species Category Total 

Injury 

(kg) 

Trophic Level Ecological 

Efficiency 

Relative to 

Benthic 

Detritivores 

(%) 

Compensatory 

Production 

(kg)a

Habitat 

Area 

(m2)b

Habitat 

Area 

(acres) 

Fish and 

Invertebrates: 

 

Small pelagic fish 217 planktivorous 20 27,113 43 0.011 

Large pelagic fish 737 piscivores 4 460,400 732 0.181 

Demersal fish 802 bottom feeders 20 100,214 159 0.039 

Demersal 

macroinvertebrates 

 706 bottom feeders 20 88,246 140 0.035 

Mollusks 14,983 filter/bottom 

feeder 

100 374,574 596 0.147 

Benthic 

invertebrates (nonmolluscan) 

 2,446 filter/bottom 

feeder 

100 61,159 97 0.024 

Birds: 

Waterfowl ( # * kg 

each) 

 65 bottom feeders 2 81,813 130 0.032 

Seabirds ( # * kg 

each) 

 80 piscivores 0.4 498,250 792 0.196 

Waders ( # * kg 

each) 

 7.2 piscivores 0.4 45,000 72 0.018 

Shorebirds ( # * kg 

each) 

 0.1 bottom feeders 2 106 0 0.000 

Raptors ( # * kg 

each) 

 16 piscivores 0.4 100,938 160 0.040 

 

Subtotal fish and 

invertebrates 

 19,891 1,768 0.44 

Subtotal birdsc 169 1,155 0.29 

Total all species 20,059 1,837,811 2,922 0.72 

a: compensatory production = total injury / ecological efficiency. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

b: habitat area = compensatory production / 628.76 kg per square meter. 628.76 kg per square meter is the marsh 

primary productivity expressed as wet weight, summed over the life of the project and discounted to account for 

timing differences between injury and restoration. Calculated totals may vary slightly from numbers presented in the 

table due to rounding. 

c: as noted in the text, scaling results for bird injuries presented here do not include ruddy ducks. 
36 

Exhibit B-6. Restoration scaling of fish, invertebrate and birds injuries using secondary (benthic macroinfauna) 

production from a Spartina saltmarsh. Saltmarsh production is assumed 77.2 g dry wt m-2 yr-1 (from Sarda et al 

1998, assuming dry weight is 15% of wet weight). Recovery is assumed to reach 80% of this rate in 15 years. 

Species Category Total 

Injury 

(kg) 

Trophic Level Ecological 

Efficiency 

Relative to 

Benthic 

Detritivores 

(%) 

Compensatory 

Production 

(kg)a

Habitat 

Area 

(m2)b

Habitat 

Area 

(acres) 

Fish and 

Invertebrates: 

 

Small pelagic fish 217 planktivorous 20 1,085 147 0.036 

Large pelagic fish 737 piscivores 4 18,416 2496 0.617 

Demersal fish 802 bottom feeders 20 4,009 543 0.134 

Demersal 

macroinvertebrates 

 706 bottom feeders 20 3,530 478 0.118 

Mollusks 14,983 filter/bottom 

feeder 

100 14,983 2031 0.502 

Benthic 

invertebrates (nonmolluscan) 

 2,446 filter/bottom 

feeder 

100 2,446 332 0.082 

Birds: 

Waterfowl ( # * kg 

each) 

 65 bottom feeders 2 3,273 444 0.110 

Seabirds ( # * kg 

each) 

 80 piscivores 0.4 19,930 2701 0.667 

Waders ( # * kg 

each) 

 7.2 piscivores 0.4 1,800 244 0.060 

Shorebirds ( # * kg 

each) 

 0.1 bottom feeders 2 4 1 0.000 

Raptors ( # * kg 

each) 

 16 piscivores 0.4 4,038 547 0.135 

 

Subtotal fish and 

invertebrates 

 19,891 6,026 1.49 

Subtotal birdsc 169 3,936 0.97 

Total all species 20,059 73,512 9,963 2.46 

a: compensatory production = total injury / ecological efficiency. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

b: habitat area = compensatory production / 7.379 kg per square meter. 7.379 kg per square meter is the marsh 

secondary productivity expressed as wet weight, summed over the life of the project and discounted to account for 

timing differences between injury and restoration. Calculated totals may vary slightly from numbers presented in the 

table due to rounding. 

c: as noted in the text, scaling results for bird injuries presented here do not include ruddy ducks. 
37 

Exhibit B-7. Restoration scaling of fish, invertebrate and birds injuries using primary (macrophyte) production from 

a Typha (cattail) marsh. Marsh production is assumed 3205 g dry wt m-2 yr-1 (from Keefe, 1973, assuming dry 

weight is 15% of wet weight). Recovery is assumed to reach 80% of this rate in 15 years. 

Species Category Total 

Injury 

(kg) 

Trophic Level Ecological 

Efficiency 

Relative to 

Benthic 

Detritivores 

(%) 

Compensatory 

Production 

(kg)a

Habitat 

Area 

(m2)b

Habitat 

Area 

(acres) 

Fish and 

Invertebrates: 

 

Small pelagic fish 217 planktivorous 20 27,113 89 0.022 

Large pelagic fish 737 piscivores 4 460,400 1503 0.371 

Demersal fish 802 bottom feeders 20 100,214 327 0.081 

Demersal 

macroinvertebrates 

 706 bottom feeders 20 88,246 288 0.071 

Mollusks 14,983 filter/bottom 

feeder 

100 374,574 1223 0.302 

Benthic 

invertebrates (nonmolluscan) 

 2,446 filter/bottom 

feeder 

100 61,159 200 0.049 

Birds: 

Waterfowl ( # * kg 

each) 

 65 bottom feeders 2 81,813 267 0.066 

Seabirds ( # * kg 

each) 

 80 piscivores 0.4 498,250 1626 0.402 

Waders ( # * kg 

each) 

 7.2 piscivores 0.4 45,000 147 0.036 

Shorebirds ( # * kg 

each) 

 0.1 bottom feeders 2 106 0 0.000 

Raptors ( # * kg 

each) 

 16 piscivores 0.4 100,938 330 0.081 

 

Subtotal fish and 

invertebrates 

 19,891 3,629 0.90 

Subtotal birds 169 2,370 0.59 

Total all speciesc 20,059 1,837,811 5,999 1.48 

a: compensatory production = total injury / ecological efficiency. Calculated totals may vary slightly from numbers 

presented in the table due to rounding. 

b: habitat area = compensatory production / 306.40 kg per square meter. 306.40 kg per square meter is the marsh 

primary productivity expressed as wet weight, summed over the life of the project and discounted to account for 

timing differences between injury and restoration. Calculated totals may vary slightly from numbers presented in the 

table due to rounding. 

c: as noted in the text, scaling results for bird injuries presented here do not include ruddy ducks. 
38 

Exhibit B-8. Restoration scaling of oyster injuries using suspension feeding production from oyster reef (199.3 g 

AFDW/m2

 = 1661 g wet weight/m2), (1) assuming the reef is seeded once in 2003, where the time for restored 

habitat to be 99% of fully functional is assumed 1 year and the project life is 5 years; or (2) assuming the reef is 

seeded once in 2003 and reseeded in 2008, where the time for restored habitat to be 99% of fully functional is 

assumed 1 year and the project life is 10 years. 

Number of Seedings Injury (kg wet weight) Reef Area (m2) Reef Area (acres) 

1: in 2003 24 15.8 0.004 

2: in 2003 and 2008 24 8.48 0.002 
APPENDIX C 

Available Data Comparing the Productivity of Phragmites to Other Types of Marsh 

Phragmites australis has expanded rapidly in areal coverage over recent decades in 

marshlands along the northern and middle Atlantic coasts. The rate and pattern of this increase 

is perceived as invasive and related to anthropogenic interference either through genetic 

introductions or disturbance (Chambers et al. 1999). Reductions in plant diversity have been 

documented where there has been a shift to dominance by Phragmites (Odum et al. 1984 cites in 

Chambers et al. 1999). However, there appears to be less quantitative evidence for a consistent 

loss of productivity and ecosystem function with a change in marsh-plant species composition. 

Productivity, energy transfer and use of habitats by faunal components do not appear to be 

related to species composition of marshes per se, but to structural conditions of the marshes such 

as tidal exchange and access pathways for fauna. For example, Meyer et al. (2001) found no 

significant or consistent difference in abundance or biomass of any fish species or of all fish 

species combined when they compared structurally and hydrologically similar stands of 

Phragmites australis and Spartina alterniflora. Marshes in each case were relatively open with 

small sinuous channels between hummocks. In comparison, distinct increases in species 

diversity and abundance were found when the channel fringe area and tidal exchange were 

increased by restoration works within a monoculture of the one salt marsh species (S. 

alterniflora; Able et al. 2000). 

Macroinvertebrate abundance does not appear to be reduced in Phragmites. Fell et. al.

(1998) found that the four most common macroinvertebrate species in Connecticut brackish 

marshes were as abundant, and often more abundant in Phragmites monocultures than in 

adjacent stands of mixed salt marsh plants (either Juscus/Spartina mix or Typha/Scirpus mix). 

Further, they found that the numerically dominant fish species, Fundulus heteroclitus was 

feeding as effectively on the macroinvertebrate prey within Phragmites as on the other marsh 

types. Thus, Phragmites is an effective foraging source and there appears to be a direct trophic 

link between Phragmites and the adjacent estuary that is at least of the same magnitude as for the 

other, mixed marsh types. 

Use of marshes by birds appears to be related to plant species, or at least to the mix of 

species. A lower number of bird species, and of saltmarsh specialist bird species, has been 

reported in stands where Phragmites was growing as a monoculture, when compared to other 

saltmarsh habitats in Connecticut (Benoit and Askins 1999). The highest species richness was 

found in marshes with the greatest diversity of marsh plants. 

Weinstein and Balletto (1999) and Chambers et al. (1999) argued that potential negative 

impacts of Phragmites on nekton can result from the build up of sediment levels and choking of 

channels, with a reduction of tidal exchange and foraging pathways. The latter cites evidence that 

this build-up restricted movement by fish and crustaceans into feeding areas of Connecticut 

marshes (M.Sc thesis by Roman, 1978). In a latter study (Windham 2001), organic and inorganic 

material was found to build-up at three times greater rate in Phragmites monocultures compared 

to Spartina monocultures due to a greater rate of production and slower rate of decay. Keefe 

(1972) and Roman and Daiber (1984) also report higher production rates for Phragmites

compared to other salt marsh plants. 
40 

The lack of quantitative production data showing net gains precludes scaling of marsh 

alteration from Phragmites to other marsh types or of restoration by channelization of 

Phragmites to improve productivity. Thus, the scaling was performed for marsh “creation” 

projects. The assumption is made that the previous biota on the restored ground were either 

undesirable or not productive for marine resources. 
41 

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