Case: World Prodigy, RI
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Final M/V World Prodigy Oil Spill Restoration Plan and Environmental Assessment Narragansett Bay, Rhode Island
Prepared by:
National Oceanic and Atmospheric Administration
National Marine Fisheries Service
Office of Habitat Protection
Restoration Center
One Blackburn Drive
Gloucester, MA 01930
March 1996
Final Environmental Assessment and Restoration Plan
World Prodigy Oil Spill Restoration Plan Narragansett Bay, Rhode Island
Lead Agency: National Oceanic and Atmospheric Administration
For further information: John Catena
National Marine Fisheries Service
One Blackburn Drive
Gloucester, MA 01930
(508) 281-9251
EXECUTIVE SUMMARY
In June, 1989 the Greek tanker World Prodigy ran aground in Narragansett
Bay, Rhode Island releasing approximately 290,000 gallons of number 2 fuel oil.
Numerous species of marine organisms were adversely affected by the spill. The
National Oceanic and Atmospheric Administration (NOAA) assesses and claims
damages (compensation) from responsible parties for injuries to natural
resources from discharges of oil, and is required to use those funds to restore
the injured resources. In 1991, NOAA received $567,299 as a result of a legal
settlement between the Federal government and the responsible party. NOAA will
use these funds to restore the natural resources injured by the spill.
The Clean Water Act, as amended by the Comprehensive Environmental Response, Cleanup, and Liability Act (CERCLA),
requires Federal and State natural resource trustees to restore, rehabilitate,
replace, or acquire the equivalent of the natural resources injured by an oil
spill. This draft restoration plan describes the proposed use of the settlement
funds received by NOAA. The proposed plan presents a summary of the incident
and injuries caused by the spill, identifies categories of restoration that
were considered (resource and habitat enhancement, acquisition of equivalent
resources, and no action), identifies criteria for project selection, and
discusses the proposed alternatives.
NOAA's goal is to restore the resources injured by the World Prodigy oil spill and compensate the public for the
lost use of those resources by enhancing habitat value for numerous marine
resources, with specific emphasis on lobsters, quahogs (hard clams), and
estuarine finfish. To meet this goal, NOAA proposes several actions: (1)
enhance lobster habitat by establishing several lobster reefs; (2) transplant
quahogs and establish quahog "spawner sanctuaries" to help restock
formerly productive areas of the bay and to make more of the resource available
to shellfishermen; (3) establish eelgrass beds in multiple sites throughout
Narragansett Bay to enhance fisheries habitat; and (4) restore a saltmarsh
system on Sachuest Point in Middletown, RI to enhance habitat for estuarine
dependent fish and shellfish.
The National Environmental Policy Act (NEPA) requires an assessment of the effects of any Federal action that may impact
the environment. This document also serves as an environmental assessment and
will comparatively evaluate alternative methods for restoring or replacing the
injured resources.
I. INTRODUCTION: Purpose and Need for Action
The World Prodigy Oil Spill and its Impact on Narragansett Bay's
Resources
On June 23, 1989, the Greek-registered oil tanker World Prodigy, owned by Ballard Shipping Company, en route from
Bulgaria to Providence, Rhode Island, grounded on Brenton Reef in Narragansett
Bay off Newport, Rhode Island (Figure 1). The impact of the grounding ruptured
nine of the vessel's 23 cargo tanks causing the discharge of approximately
290,000 gallons of number 2 fuel oil into the bay. The oil eventually spread
over a 123 square mile area of the bay and Rhode Island Sound. A portion of the
oil was stranded on intertidal areas of lower Narragansett Bay. The spill
adversely affected numerous species of marine organisms including large numbers
of adult crustaceans, fish, shellfish and crustacean eggs and larvae, and a
variety of benthic organisms in certain heavily oiled locations (Pilson 1989).
Additionally, various human uses were adversely affected. The entirety of
Narragansett Bay was closed to shellfishing as a precautionary measure for one
week leading to a loss of access to shellfishing grounds for commercial and
recreational clammers. Many of the state's beaches also were closed for up to
two months, in some cases, though most were closed for several days.
Data collected by NOAA's National Marine Fisheries Service and other agencies suggested that the World Prodigy spill
killed a significant number of planktonic life forms, larval and juvenile fish,
and larval shellfish and crustaceans. Species that were adversely affected
included significant numbers of early life stages of tautog, cunner, scup, sea
robin, and larval lobsters (K. Sherman, National Marine Fisheries Service,
pers. corr. 1989). The greatest proportion of NOAA trust resource losses were
annually spawned pelagic juveniles. Their deaths represented the loss of a
significant portion of the 1989 year class of those species within the impacted
area (K. Sherman, NMFS, personal communications). Analysis of the data obtained
by the State of Rhode Island, The University of Rhode Island, NOAA, the Food
and Drug Administration, the U.S. Environmental Protection Agency and the U.S.
Coast Guard demonstrated that the quahog or hard clam (Mercenaria mercenaria),
American lobster (Homarus americanus) and a variety of finfish eggs and
larvae were among the most seriously impacted of the NOAA trust resources in
Narragansett Bay.
The shores of Conanicut Island were most affected. The Rhode Island Division of Fish and Wildlife conducted shoreline
surveys at Mackerel and Hull Coves in Jamestown, RI and collected over 800
dead, small lobsters and crabs in those two locations. The total number may
have been considerably greater since it is probable that not all carcasses were
washed ashore and many could have been carried away by scavengers (gulls,
foxes, skunks, and raccoons) (Pilson, 1989). Though the oil spread throughout a
large area in Narragansett Bay and Rhode Island Sound, within days the oil had
largely disappeared from the surface waters as a result of evaporation and
mixing in the water column (Pilson, 1989). However, data collected for several
years following the spill indicated that significant concentrations of oil
remained in the beach sand in Hull Cove (Mulhare and Therrien, 1993).
Extrapolation of that data suggests that degradation of the oil would slowly
continue with significant concentrations remaining for at least five years
after the spill (Mulhare and Therrien, 1993).
In addition to the scientific sampling performed by the various Federal and state agencies, and academic institutions, a
computer model was run to simulate the effects of the spill on the bay's
resources. The Natural Resource Damage Assessment Model for Coastal and Marine
Environments ("Type A Model") was used to estimate damages caused by
the spill. The model uses a variety of inputs including air and water
temperature, current and wind data, type and amount of oil spilled, and
resources present in the impact area, to calculate injuries to the affected
resources. The modeling results were similar to the data collected, however,
the model predicted large numbers of adult fish kills where sampling did not
detect any (French, et al., 1990).
Generally, refined petroleum products such as number 2 fuel oil (home heating oil) have greater concentrations of toxic
components (i.e., aromatics) than crude oil. Consequently, spills of refined
products are likely to have a greater ecological impact (Malins, 1977). The
high content of toxic aromatics was one reason for the severity of effects of
the 1969 spill from the barge Florida in West Falmouth, Massachusetts
(Mielke, 1990). That spill released 4,500 barrels of number 2 fuel oil into
Buzzards Bay. Number 2 fuel oil, as well as the other light oils, can have
long-term impacts on intertidal resources. Although number 2 oil is considered
to be moderately volatile, evaporation is not as complete as with a lighter
fraction such as gasoline. Number 2 fuel can leave a residue, up to one-third
of the spill amount. Porous sediments absorb this fuel oil rapidly; the
petroleum moves downward as far as the water table allows. Refractory portions
of the oil spilled at West Falmouth still remain in the sediments (Boesch, et al.,
1974; Mielke, 1990; Teal et al., 1992).
The impact that no. 2 fuel oil has on an organism depends on environmental and biological factors, as well as oil
concentration. Cardwell (1973) found that toxicity of no. 2 fuel oil increases
concomitantly with increasing temperature. Heavy oil contamination results in
the death of marine and salt marsh animals, particularly benthic animals (Burns
and Teal, 1979; Pilson, 1990). In general, sensitivity to oil varies with life
stage and species, with eggs being the most sensitive, and adults being the
least.
The ability of an organism to avoid a contaminant is a major determinant in its ability to survive an oil spill.
Generally, finfish are less at risk due to their motility; they can leave the
area of degradation (RPI, 1989). Crustaceans are generally more sensitive than
bivalves; since the latter can close their shells for extended periods. The
marketability of bivalves, however, can be severely impacted. Even if they
survive an oil spill, they still may be unfit for human consumption. Bivalves
surviving the initial toxic dosing can accumulate oil in their tissues in the
course of normal feeding. Clark (1989) reported that tainting, or becoming oily
tasting, can occur at very low levels of contamination (a few parts per
million) and remain present even after four weeks of attempted depuration.
During harvesting, even a small quantity of oil on harvesting gear or a few
organisms can taint the whole catch and render it worthless. Handling and
processing quickly spread the tainting substance throughout the catch.
Settlement
A $3.9 million settlement resolving all Federal claims for response, clean up and injuries to natural resources was
reached with the responsible party by the U.S. Government in 1991. NOAA
received $567,299 to be used for restoration to compensate for injuries to
natural resources. The remaining balance went to the Coast Guard and other
Federal agencies for reimbursement for response and clean-up costs. The Under
Secretary for Oceans and Atmosphere (NOAA Administrator), on behalf of the
Secretary of Commerce, acts as a Federal trustee for natural resources under
the Comprehensive Environmental Response, Compensation and Liability Act of
1980, the Clean Water Act, the Marine Protection, Research and Sanctuaries Act,
and the Oil Pollution Act of 1990. Under these laws, NOAA acts on behalf of the
public to assess and claim damages (compensation) for injuries to natural
resources from discharges of oil or releases of hazardous substances, and to
use the recovered damages to restore, replace, or acquire the equivalent of the
injured resources. This proposed restoration plan was drafted to fulfill NOAA's
requirements under these authorities.
Proposed Actions
The goal of the proposed restoration efforts is to restore the resources injured by the World Prodigy oil spill
by enhancing habitat value for numerous marine resources, with specific
emphasis on lobsters, quahogs (hard clam), and estuarine finfish. Projects were
developed to address these resources because they were the most significantly
affected by the oil spill. In order to meet this goal NOAA proposes several
actions: (1) enhance lobster habitat by establishing several lobster reefs; (2)
transplant quahogs and establish quahog "spawner sanctuaries" to help
restock formerly productive areas of the bay and to make more of the resource
available to shellfishermen; (3) establish eelgrass beds in multiple sites
throughout Narragansett Bay to enhance fisheries habitat; and (4) restore a
saltmarsh system on Sachuest Point in Middletown, RI to enhance habitat for
estuarine dependent fish and shellfish.
Lobster reefs. To restore the lobster resource injured by the oil spill, NOAA proposes to establish six
artificial reefs measuring 10 meters by 20 meters made of various sizes of
cobble and boulders in the lower west passage of Narragansett Bay (Figure 1).
We propose to place all six reefs in 20 30 feet of water off the Bonnet Shores
area. The specific locations within this general area will be chosen in
consultation with local fishermen and based on a side-scan sonar survey and
current data. A total of 450 m3 of cobble and boulders will be used covering
1,200 m2 of bay bottom.
Quahog transplant and spawner sanctuaries. To compensate for the lost use of clam beds and restore the quahog
resource injured by the oil spill, NOAA proposes to transfer a portion of the
settlement funds to the Rhode Island Department of Environmental Management to
be used to fund the transplanting of quahogs from restricted waters to two
"spawner sanctuaries" at the mouth of Greenwich Bay and near Gould
Island in the Sakonnet River (Figures 2 and 3). Quahogs will be transplanted to
these locations and will be off limits to harvesting for two years.
Eelgrass bed restoration. To restore estuarine finfish injured by the oil spill, NOAA proposes to establish
eelgrass beds at approximately 10 different locations throughout Narragansett
Bay. Sites will be identified following site surveys and consultation with
local investigators. Selection will be based on water quality conditions,
sediment particle size, historical evidence of presence of eelgrass, degree of
exposure to waves and tidal currents, and existing uses.
Salt marsh restoration. To restore estuarine finfish injured by the oil spill, NOAA proposes to restore a salt
marsh in the Sachuest Point National Wildlife Refuge in Middletown, RI (Figure
4). This marsh has been degraded by inadequate tidal flow caused by road
construction and an inadequately sized culvert. Tidal flow will be restored by
replacing the culvert with two larger culverts and clearing the tidal creeks of
excess sedimentation. Restoration of tidal flow should restore the marsh's
natural vegetation and increase fish access to the marsh thereby enhancing the
production of estuarine fish.
II. AFFECTED ENVIRONMENT
This section describes the environment affected by the T/V World Prodigy oil spill (the World Prodigy site)
including a general description of the physical, biological, and cultural
environments. All descriptions are non-technical. Citations refer the reader to
more detailed information.
In 1989 dollars, Narragansett Bay generated almost $2.5 billion in revenues for the State of Rhode Island based on
direct exploitation of the bay's fisheries, tourism, marine-related industry,
marine research and education, and U.S. Navy-related activities (NBP, 1992).
The major contributing sectors to this annual revenue include fish and
shellfish harvesting, marine transportation, national defense, education,
scientific research, and recreational activities. Many of these and other
economically important activities associated with the bay depend on the
productivity and functions of coastal and marine habitats found along the Rhode
Island shoreline.
Physical and Biological Environment
Rhode Island is located along the southern coast of the New England region of the United States. The climate of the
state is influenced by oceanic processes and is characterized by moderately
cold winters and mild summers. Rhode Island contains numerous coastal,
estuarine, and oceanic natural resources distributed along its 419 miles of
coastline (Seavey, 1975). The most prominent of these features is Narragansett
Bay.
Narragansett Bay is considered the state's most valuable natural resource (NBP, 1992). The bay is a 147 square mile
glacially carved, drowned river estuary that dominates the physical geography
of Rhode Island. The watershed of the bay encompasses 1,657 square miles within
Rhode Island and Massachusetts (NBP, 1992). Narragansett Bay is influenced by
marine waters via Rhode Island Sound at its southern end, and by freshwater
inputs from numerous rivers, streams, ponds, industrial plants, sewerage
treatment facilities, precipitation and other sources throughout the watershed.
It is estimated that the bay receives 2,400 million gallons of freshwater
everyday (Pilson, 1985; Ries, 1989). The salinity of the waters of the bay are
distributed across a north south gradient from the fresher upper bay areas
(15%) to the saline lower reaches of the mouth (33%) (Bricker, 1993). The
average depth of the bay is 27 feet with some areas (East Passage) having an
average depth of 50 feet (NBP, 1992). The northern portion of the bay is
surrounded by the heavily urbanized area of Providence and contains sediments
that reflect the years of human and industrial waste disposal in the bay. The
lower portion of the bay is surrounded by less densely populated communities
and is generally characterized by less contaminated habitats.
The shoreline and waters of Narragansett Bay contain approximately 4,800 acres of coastal wetlands (RIDOA, 1988).
Coastal wetlands in Rhode Island include salt marshes, freshwater marshes,
forested wetlands, emergent wetlands, scrub-shrub wetlands, seagrasses, and
tidal flats (Tiner, 1989). These coastal habitats support populations of
wildlife including birds, fish, insects, mammals, and reptiles. Extensive
scientific investigations have been conducted within the salt marshes of the
bay by scientists at the University of Rhode Island Graduate School of
Oceanography (University of Rhode Island, 1972). Salt marshes cover about 2800
acres of land around Narragansett Bay and fringing marshes line some 80 km of
the bay shoreline. These intertidal wetlands, located along the bay shore and
tributaries, serve as habitat for many important commercial and recreational
marine fish species and other organisms that form critical links in the food
chain of the bay ecosystem (Nixon and Oviatt, 1973; Nixon, 1982). It is
estimated that 15 30% of the fisheries landed in Rhode Island waters are
dependent upon estuarine wetlands (Greg Miller, National Marine Fisheries
Service, pers. comm.).
Intertidal flats are composed of mud and sand sediments that occur between the limits of low and high tide and encompass
some 4400 acres around Narragansett Bay (NBP, 1992). The utilization of tidal
flats by numerous species of fish is also determined by water temperature and
other factors such as tide level and time of day. Tidal flats are dominated by
benthic worms and epibenthic crustaceans (Whitlach, 1982). These areas are
believed to have few vertebrate residents, but instead are seen as areas
"for the conversion of plant production into animal biomass" and that
are interconnected to other coastal habitats (Whitlach, 1982). Tidal flats are
also utilized as feeding and resting areas for migrating shorebirds such as
sandpipers, and as foraging areas by other birds including herons, gulls, and
terns (Whitlach, 1982). Many species of birds and fish alternate feeding
between tidal flats and salt marshes in response to the tidal cycle.
The bay also contains eelgrass (Zostera marina) beds that function as finfish and shellfish habitat, sediment
traps, nitrogen fixers, and wave energy absorption areas (Thayer et al.,
1984; Adamowicz, 1994). Seagrass beds were once found throughout some shallow
areas of the bay. The decline is believed to have been caused by wasting
disease, elevated nutrient loadings, increased turbidity, navigation channel
construction and other forms of anthropogenic habitat destruction (Thayer et al.,
1984).
Sandy beaches are extremely important to the Rhode Island economy which is heavily dependent upon summer tourism
(University of Rhode Island, 1994). Most of the state's sandy beaches are
located outside of the bay along the shores of Block Island Sound. However,
there are several significant sandy shorelines within the lower reaches of the
bay especially at Narragansett Pier, Scarborough Beach, and Newport (Olsen and
Grant, 1973). These coastal barriers provide foraging grounds to shore birds
and mammals, as well as intertidal habitat for marine crustaceans and molluscs.
Barrier beaches provide storm surge protection for coastal development and
serve to moderate oceanic influences upon back barrier habitats such as salt
ponds and coves. These and other coastal natural areas serve as recreational
areas for residents and tourists, and provide habitat for important biological
resources.
Narragansett Bay provides important fishery habitat for anadromous species, estuarine and marine finfish, shellfish and
numerous other non-commercial but important lower trophic- level species (NBP,
1992). Commercial fisheries harvests in the state had a dockside value of $76
million in 1993 (U.S. DOC, 1994). The quahog (Mercenaria) is the most
important commercial fishery within the bay (NBP, 1992; Pratt et al.,
1992) and supports over 2,000 jobs. Other important commercial stocks harvested
from the bay include winter flounder (Pleuronectes americanus), lobster
(Homarus americanus), menhaden (Brevortia tyrannus), and
butterfish (Poronotus triacanthus) (see Olsen and Stevenson, 1975).
Recreational fishing is estimated to generate more than $18 million of annual
economic activity in Rhode Island (McConnell, et al., 1981). Both
commercial and recreational fisheries in Narragansett Bay are imperiled by
over-utilization, habitat loss, and various types of pollution (NBP, 1992).
These valuable fisheries can be maintained only through efforts to effectively
manage fishing pressure, protect critical estuarine habitats, reduce pollution
inputs, and initiate watershed-based ecological restoration.
Endangered and Threatened Species
Numerous Federally endangered and threatened species are seasonal or occasional visitors to Narragansett Bay. Several
species of sea turtles may be present from June through November as wanderers
in the bay. These include the threatened Atlantic loggerhead (Caretta),
and the endangered Atlantic leatherback (Dermochelys coriacea), Atlantic
Kemp's ridley (Lepidochelys kempi), and the green sea turtle (Chelonia
mydas) (D. Beach, NMFS pers. comm; Gould and Gould, 1992). The loggerhead,
Kemp's ridley and green sea turtles are mostly juvenile and subadult
individuals foraging in nearshore coastal waters. The Kemp's ridley appears to
prefer estuarine areas where green crabs and mussels are found. Loggerheads
feed on benthic organisms found in large bay systems and leatherbacks forage in
the open waters in search of jellyfish. Several whale species (humpbacks,
finback, and right whales) may transit the mouth of Narragansett Bay and Rhode
Island Sound but do not typically enter the bay. Threatened or endangered bird
species inhabiting the bay include the endangered bald eagle (Haliaeetus
leucocephalus), peregrine falcon (Falco peregrinus), roseate tern (Sterna
dougallii), and the threatened piping plover (Charadrius melodus)
(Gould and Gould, 1992). The bald eagle, which is a rare migrant and winter
visitor is most commonly found in salt ponds. Peregrine falcons are uncommon
migrants usually seen in nearshore and tidal flat areas. The roseate tern is an
uncommon summer breeder which favors rocky shores and islands for breeding. The
piping plover is an uncommon migrant and summer breeder preferring sandy
beaches for breeding and feeding (Gould and Gould, 1992).
Historic and Cultural Resources
The earliest evidence of human habitation of the Rhode Island coast dates back to 6,500 B.C. (Hale, 1980). Narragansett
Bay has been a centerpiece of activities associated with local native American
populations, the development of colonial America, the birth of the industrial
revolution, the defeat of the Axis forces in World War II, and the origin of
scientifically based coastal zone management planning. Fish, shellfish, and
other natural resources have been exploited by the region's inhabitants for an
estimated 8,500 years (Hale, 1980). The aboriginal, colonial, industrial, and
modern inhabitants of the Narragansett basin have all utilized the natural
resources of the bay leaving behind a rich history of their different coastal
dependent cultures. Remnant cultural resources of the historic occupants of the
bay watershed are believed to be widely distributed in the estuary and along
its shores. These resources include native American Indian settlements,
battlegrounds, farms, buildings, shipyards, wharves, religious sites, and other
aspects of the area's heritage. The State of Rhode Island has established a
protection program for these resources that utilizes a predictive model to
designate areas that are historically or archaeologically sensitive. The
majority of historic sites in the state are located within the coastal zone and
therefore are the most threatened because of natural processes, as well as
human development pressures. The Rhode Island Coastal Resources Management
Program contains a policy statement to protect cultural resources within the
state's coastal zone (Olsen and Seavey, 1983). Any action(s) undertaken to
restore the natural resources impacted by the World Prodigy oil spill
must comply with the historic and archaeological protection guidelines outlined
by the state's approved coastal zone management plan.
III. PROPOSED ACTIONS AND ALTERNATIVES
This section describes the actions NOAA considered to restore the resources
injured by the World Prodigy oil spill. As discussed above, The Clean
Water Act, as amended by CERCLA, requires NOAA to use settlement funds
recovered from responsible parties to "restore, replace, or acquire the
equivalent of the injured natural resources." NOAA considered three
categories of activities: habitat restoration/resource enhancement; habitat
acquisition; and no action. The environmental consequences of each of the
aforementioned categories and alternatives is presented and discussed in this
chapter. Monitoring methodologies for each of the preferred alternatives is
also discussed.
The goal of the proposed actions is to enhance habitat value for a variety of marine resources with specific emphasis on
quahogs (hard clams), lobsters, and estuarine finfish. This goal was developed
because the spill adversely affected large numbers of the eggs, larvae and
adults of these resources and because the public was prohibited from harvesting
some of these resources during a period after the spill. To meet this goal NOAA
proposes several actions: (1) enhance lobster habitat by establishing several
lobster reefs; (2) transplant quahogs and establish "spawner
sanctuaries" to help restock formerly productive areas of the bay and to
make more of the resource available to shellfishermen; (3) establish eelgrass
beds in multiple sites throughout Narragansett Bay to enhance fisheries
habitat; and (4) restore a saltmarsh system on Sachuest Point to enhance
habitat for estuarine dependent fish and shellfish.
A monitoring program will be implemented for each effort to evaluate its effectiveness. A requisite to any restoration
project is a well designed and cost-effective monitoring effort. Such an effort
forms the foundation and is a prerequisite of restoration plans because it is
the sole means of providing a measure of the viability, stability and
persistence of the restoration and, therefore, an assessment of the effective
use of the settlement funds. The monitoring plan will provide the necessary
information to establish criteria for and evaluate the need for mid-course
corrections, should they be necessary.
Each alternative discussed below was evaluated based on the following criteria: (1) the project must restore resources
injured by the spill; (2) the project must be cost effective; and (3) the
project should use a proven technique and have a relatively high probability of
achieving the restoration goal. Those projects which could not satisfy all of
those criteria were eliminated from consideration. Table II at the end of this
chapter summarizes the results of the criteria evaluation for each alternative.
While there are more projects that can meet the above criteria than there is
available funding, NOAA has determined that the proposed actions will be the
most effective means to restore the injured resources.
1. Habitat Restoration/Resource Enhancement
In this category, several projects are considered to restore or enhance the resources and services injured by the World
Prodigy oil spill. Seven alternative projects are considered, four of
which are proposed. The proposed projects (letters A-D) are discussed first
followed by the rejected proposals (letters E-G). General costs are provided
for the proposed actions. Detailed budget information is available from NOAA at
the address and phone number listed on the front cover page.
A. Lobster Habitat Enhancement (Preferred Alternative)
Hundreds of adult lobsters and other crustacea and untold numbers of their larvae were killed by the World Prodigy
oil spill. To address these injuries to the lobster population in Narragansett
Bay, NOAA proposes to enhance habitat for lobsters and associated fauna by
establishing several rocky reefs in the bay, tagging and seeding the reef with
hatchery-reared lobsters, and monitoring the development of the lobster
population in this new habitat. A limited number of hatchery-reared lobsters
will be tagged and used to seed the reef to monitor their development and to
test the efficacy of stocking hatchery reared-lobsters using coded micro-wire
tags. NOAA will issue a contract for the purchase and construction of the
lobster reef and will issue a grant to the University of Rhode Island to
conduct the design and monitoring work.
The enhancement of marine resources, either to enhance harvests or to restore losses, has a long history. Methods to
enhance fishery resources include regulating fishing effort to reduce pre
recruit mortality or increase survival of breeding stock, adding
hatchery-reared animals, increasing useful habitat, and protecting breeding
stock in sanctuaries (Conan, 1986; Addison and Bannister, 1994). When habitat
has degraded due to natural or anthropogenic causes, restoration of the habitat
is appropriate to allow populations to return to pre-disturbance levels,
assuming the cause of the degradation has been removed or is below acceptable
levels.
Lobster Life History and Biology
The American lobster, Homarus americanus, is one of the largest and most valuable crustaceans in the world. It is
found from the intertidal zone to depths of 700 m along the northeast coast of
North America from New Jersey to Labrador. Lobsters have been studied
scientifically for over one hundred years. A commercial fishery developed in
the United States and Canada during the mid- 1800s and currently supports a
large and valuable industry in both countries (Fogarty, in press).
The life cycle of the American lobster is reasonably well understood. Females mature at sizes ranging from 60 to 105 mm
carapace length (CL) and hatch their eggs into the water column where the
larvae remain for between 11 and 54 days (MacKenzie, 1988). The developing
larvae and postlarvae are transported considerable distances (e.g., Katz et al.,
1993). The postlarva swims at the surface for several days, then makes the
transition from pelagic to benthic habitat, settling and remaining for several
years in shallow, cobble substrata (Hudon, 1987; Wahle and Steneck, 1991).
Early benthic phase lobsters are cryptic and quite restricted in habitat use
(Wahle and Steneck, 1991); they probably do not emerge from their shelters
until reaching a size of about 25 mm CL (Wahle, 1992; Cobb and Wahle, 1994).
Larger, but still sexually immature adolescent phase lobsters are found on a
variety of bottom types, usually characterized by an abundance of potential
shelters. Inshore, they are found in greatest abundance in rock and boulder
areas (Cooper and Uzmann, 1980). There are very few data on the density of
lobster populations. Surveys by divers have provided estimates ranging from 70
to 32,500 lobsters per hectare in inshore rocky areas (Cobb and Wang, 1985). In
Rhode Island and Connecticut, densities of approximately one lobster per 10 m2
were reported by Cobb (1971) and Stewart (1970) in rocky habitat. Juvenile
lobsters seldom move more than a few kilometers (Wilder, 1963). Once mature,
animals may range over 30 km annually and some travel as far as 100 km or more
on cross-shelf migrations (Cooper and Uzmann, 1971) or along the coast
(Campbell and Stasko, 1985).
Habitat Enhancement Efforts
Previous attempts to increase lobster populations in local areas through habitat enhancement have been successful. A
relatively systematic habitat enhancement effort was conducted in Rhode Island
waters (Sheehy, 1976). Artificial shelters, made of pumice concrete, were
placed on featureless sand substrate in the Point Judith Harbor of Refuge.
Lobsters of all sizes, including newly settled lobsters, colonized the shelters
quickly, as did other species of crabs and fish. Design of the shelter was
important: the triple chamber design was used by a larger number of lobsters
than was the single chamber design. Lobsters both used the chambers and
burrowed underneath the solid portions of the concrete blocks. Orientation of
the shelter was important for hydrodynamic reasons. Currents, particularly
during storms would scour around the shelters or flip them over.
An artificial reef made of 8 heaps (1 x 4m) of blocks fabricated from pulverized fuel ash covered an area of 10 m x 30 m
in Poole Bay, England. The reef was situated approximately 3 km from hard
substrate inhabited by lobsters. Within three weeks after deployment of the
reef, lobsters (H. gammarus) were found on the reef by divers.
Population estimates of lobsters on the reef are in the range of 20-30 animals
per 100 m2. Most of the movement of tagged lobsters seen was between units of
the reef, and residence times on the reef were high. Several tagged individuals
were resampled several times over a period of more than a year (Jensen et al.,
1994.)
A large rock reef (2740 m2) was built in eastern Canada and the development of the lobster population followed for 7
years. During the first two years, the reef was colonized by lobsters larger
than the average size of individuals in nearby natural areas, and the biomass
was lower. However, after 5 years, the size distribution of lobsters on the
reef was similar to natural ground, and the biomass was higher than neighboring
areas (Scarratt, 1968, 1973). The characteristics of a good artificial reef for
lobsters were described by Spanier (1994). These include being a good
recruitment substrate for postlarvae and juveniles, and being a refuge from
predation for all stages. Adequate shelter and food resources also are
important to the maintenance of a population on an artificial reef. Placement
of the reef in a location where lobsters of all sizes will recruit to it also
is important.
Project Description Overview NOAA proposes to establish six artificial reefs made of various sizes of
cobble and boulders in the west passage of Narragansett Bay. All six reefs will
be placed on sandy bottom in approximately 20-30 feet of water off the Bonnet
Shores area (Figure 1), where both lobstering activity and earlier sampling
have demonstrated a naturally occurring population. The specific locations
within this general area will be chosen in consultation with local fishermen.
Areas where quahogging is common, or where draggers frequently work will be
avoided.
The proposed reef location in the lower West Passage, off Bonnet Point in Narragansett is reported in the Narragansett
Bay Project Habitat Inventory to be "marine sand." Pratt (University
of Rhode Island, personal communication) subclassifies the area as "bay
mouth wave-washed sand." McMaster (1960) classified the area as
"sand" and noted that the clay content was less than 10%. Little
sampling for benthic fauna has been done in this area. The surf clam, Spisula,
is found and occasionally harvested in the vicinity. A few specialized forms of
benthic fauna adapted for mobile sands would be expected to inhabit this area.
At the mouth of the Sakonnet River, where similar substrate is found, the
benthos includes the capitellid Amastigos caperatus, two species of the
polychaete Arcia, the predatory polychaete Nephtys picta,
Haustoriid amphipods, and beds of the sand dollar Echinarachnius parma (S.
Pratt, personal communication).
The reefs should become populated by newly settled lobsters and lobsters that migrate in from nearby, natural areas. The
development of the population on the reefs will be followed over time. In
addition, hatchery-reared lobsters will be released onto the reefs. This may
augment the natural population and test the question of whether hatchery
releases have an impact on lobster density. The impact of the reefs on the
density of lobsters in the area where the reefs are placed will be evaluated
using a Before/After-Control/Impact (BACI) design which addresses the needs for
replicated sampling in time and in space and the comparisons of control
(unaltered) areas to the affected area (Underwood, 1992).
Reefs A total of six small reefs are proposed. Each of the artificial reefs will be composed of an area of cobble
(small rocks 3-10 cm diameter, see Wahle and Steneck, 1991; Wahle, 1992) and an
area of larger rocks and boulders (20-40 cm diameter). This range of substrate
sizes will provide refuge for the whole span of lobster size (Wahle, personal
observation). As a lobster grows, it outgrows the habitat it first selects and
must move to new habitat where larger crevices are available (Wahle, 1992;
Caddy and Stamotopoulos, 1990.) Each reef will be 10m x 20m. Vertical relief
will be on the order of 1/4m in the cobble section and 1/2m in the rock/boulder
section. A total of 450 cubic meters of cobble and boulders will be used,
covering a total area of 1,200 square meters. The reefs will be established
with a barge and crane operation with the rocks being placed on the bay bottom
by the crane.
In order to locate the reefs in a suitable area where they will not be covered by moving sand, or be placed on top of
existing lobster habitat, a survey using side-scan sonar will be conducted. The
results of the survey will be interpreted using information about current speed
in the area (available from earlier work by M. Spaulding, URI)
Release of hatchery-reared lobsters Approximately 600-1000 juvenile (fifth-stage), hatchery-reared lobsters will
be released onto each reef each of the first three years in the early summer to
determine the effects of stocking on lobster population size on the reefs. Each
individual will be tagged with a coded microwire tag. The tags are retained
through molting and thus can be used to identify individuals seeded onto the
reef and distinguish them from individuals that settled naturally.
The early benthic stage lobsters seeded on the reefs will be the progeny of females captured in Narragansett Bay. Egg
bearing females will be brought into a laboratory at the University of Rhode
Island's Graduate School of Oceanography and allowed to hatch their eggs on a
normal schedule. The larvae will be reared, using standard techniques, in
kriesels designed to keep the larvae moving and apart from one another. Animals
will be maintained in the kriesels until the fifth stage is reached. At that
point, they will be tagged, held for two or three days in individual
compartments to ensure that tag-related mortality is low, and then released by
divers on the reefs.
Monitoring Monitoring will be conducted over a period of five years to quantify the impact of the deployment of
the artificial reefs on the local lobster population. Divers using standard
visual and air-lift census techniques will assess the number and size of
lobsters on the reef at defined intervals for five years. Nearby natural
lobster grounds also will be monitored. The population density, size and sex
composition of natural and artificial lobster habitat will be compared. To
monitor the development of the lobster population on the reefs, divers will
census each reef on a regular basis. At least one (if possible, more) census
will be made during the month before the reefs are installed. Monitoring is
also proposed for the presence and relative abundance of species of larger
invertebrates, fishes, and macroalgae (% cover) on the reefs. All small
lobsters captured on the reef and in nearby natural areas will be screened for
the presence of a microwire tag. This will allow us to determine the effect of
stocking, and, depending upon emigration, provide estimates of mortality and
carrying capacity. To provide an estimate of the longer-term effectiveness of
the larval stocking effort, commercial and scientific fishing on the artificial
reefs will be performed on a weekly basis in the final year of the project. All
captured lobsters will be scanned using a magnetic scanner to determine the
presence of the coded micro-wire tags. Monitoring activities will address the
following:
-
To quantify the impact of the reefs on the density of lobsters, the number of
lobsters in nearby sandy habitat will be compared to those at the reef site.
-
Do specific population parameters (density, size distribution, sex ratio) of
lobsters on the artificial reef differ from those of lobsters in natural rock
and cobble areas nearby?
-
Do the measured population parameters (above) change over time as the reef
ages?
-
Does the size of the cobble affect the recruitment of lobsters to the reef?
-
Does the seeding of early benthic phase lobsters affect population density on
the reef when compared to unseeded reefs?
-
Does the rate of loss of seeded lobsters vary with cobble size?
-
Is there movement of marked lobsters from areas of small cobble to areas of
larger rocks as the lobsters grow larger?
Costs
1. Six 10m x 20m artificial reefs, as described above will cost approximately $50,000 for purchasing and hauling the
cobble and boulders and labor for operating the barge, crane, and tug.
2. Personnel, supplies and boat time for tagging, seeding, and monitoring for five years is estimated at $220,000.
Environmental Consequences
Establishing six cobble/boulder reefs appropriate for a wide size range of lobsters should attract and retain newly
settling lobsters as well as "walk-ins." This should allow the reef
to develop a population of lobsters similar in size and structure to those
found in natural substrate areas. The reefs will displace the existing sandy
substrate and its associated fauna. A total of 1,200 square meters of bottom
will be covered by the reefs. In its place the reefs should attract fauna
associated with rocky subtidal environments typical of those in Narragansett
Bay. This type of community consists of such species as tautaog, cunner,
sculpin, sponges, sea anemones, crabs, lobsters, encrusting algal species, sea
stars, barnacles, bryozoans, gastropod molluscs, mussels, and others.
Criteria Evaluation
This project addresses injuries to lobsters caused by the World Prodigy oil spill. Artificial reefs for lobsters
have been successfully implemented in a variety of locations and settings
(Scarrat, 1968, 1973; Sheehy, 1976; Jensen, et al., 1994). In addition,
lobster habitat has been studied extensively in Narragansett Bay and elsewhere
(Incze and Wahle, 1991; Wahle and Steneck, 1991;1992; Wahle, 1993; ). This
project will attempt to create lobster habitat which mimics their habitat found
in nature. Based on previous studies, it is expected that the reef will be
colonized rapidly by lobsters and other organisms. The cost of creating the
habitat is relatively inexpensive given the potential benefit to injured
fishery resources. An additional amount of the project budget is devoted to
monitoring to ensure the success of the project, to make any necessary
mid-course corrections, and to develop new information on the relative
effectiveness of artificial reefs.
B. Quahog Spawner Sanctuary in Narragansett Bay (Preferred Alternative)
During the World Prodigy oil spill the entirety of Narragansett Bay was closed to all shellfish harvesting as a
precautionary measure to protect public health. Though no documented injuries
occurred to adult quahogs, commercial and recreational clammers lost access to
the quahog resource for the closed period and shellfish larvae were killed by
the spill. To address these injuries, NOAA proposes to transfer a portion of
the settlement funds to the Rhode Island Department of Environmental Management
(RIDEM) quahog spawner sanctuary program to expand their efforts. The RIDEM has
a long history of transplanting quahogs from restricted areas to areas of the
bay open to harvesting to allow shellfishermen access to the resource. The
spawner sanctuary program attempts to reestablish clam beds in selected parts
of Narragansett Bay. The objective of this project is to increase the number of
harvestable quahogs to compensate recreational and commercial shellfishermen
for the lost use of the bay during the oil spill. An additional objective of
the project is to re-establish quahog populations in areas which previously,
but no longer contain significant quantities of the resource.
Spawner sanctuaries have been used as a fishery management tool for decades. Such areas are closed to harvesting of
living resources for a defined period of time to protect local populations of
the resource so they can increase in abundance. A quahog spawner sanctuary
established by the State of Rhode Island in Quonochontaug Pond has resulted in
increased density throughout the pond over a four-year period (Ganz, 1988). The
Rhode Island Marine Fisheries Council has recently established two quahog
spawner sanctuaries in Narragansett Bay. The State of Rhode Island also has
funded annual quahog transplants from areas that are closed to harvesting (due
to fecal coliform contamination) to management areas to allow for spawning,
depuration, and subsequent harvesting. Both the transplant and sanctuary
programs rely on members of the industry to collect and move shellfish to the
selected sites.
Methodology
Two areas of Narragansett Bay have been designated as spawner sanctuaries through regulations promulgated by the Rhode
Island Marine Fisheries Council (Figures 2 and 3). One site is located at the
mouth of Greenwich Bay (Figure 2). The site is irregularly shaped and
encompasses the waters south of a line between the flagpole at the Warwick
Country Club and the seaward end of Sandy Point; north of a line between the
Warwick lighthouse and the seaward end of Pojac Point including all the waters
of the Potowomut River. The second location is in the upper Sakonnet River in
the vicinity of Gould Island (Figure 3). This rectangular shaped site includes
most of the waters of the upper Sakonnet River to the north of Gould Island.
These sites were selected because they were once productive areas which are
currently depleted.
Shellfish densities and presence of predators in the sanctuaries will be determined prior to transplant operations. If
predators such as starfish, crabs, and whelks are determined to be a potential
problem, they will be removed from the sanctuary sites by dredging or mopping
to protect newly settled quahogs from predation while the bed is being
established. Once the bed is established newly settled clams will no longer
need the added protection that mopping provides.
Shellfish will be transplanted to each site in two successive years. Quahogs will be harvested and transplanted in the
spring by commercial shellfishermen or a dredge boat from uncertified waters
and used as the brood stock in the established spawner sanctuaries.
Transplanting in the early spring will enable the quahogs to undergo a normal
spawning cycle during the summer months. The quahogs will be transported by
vessel to the sanctuary sites and planted. It is expected that approximately
200,000 pounds of quahogs will be transplanted to the sanctuary sites in each
of the two years of the project. Harvesting from the sanctuaries will be
prohibited for two spawning seasons. Increasing the spawning population density
within these areas is expected to improve fertilization and larval distribution
within the sanctuaries and adjacent waters. The presence of potential predators
will be monitored by direct observation using divers, test tows, and mopping on
a seasonal basis and controlled during the course of the two years. A
population survey will be conducted prior to reopening the areas to harvesting.
Costs
Costs for RIDEM enforcement staff, monitoring, equipment, and contracts with local shellfishermen or a dredge boat to
harvest and transplant quahogs will be approximately $75,000.
Environmental Consequences
Transplanting quahogs from one area of the bay to another will have minimal impact on the environment. Commercial
shellfishermen will harvest quahogs from closed areas using bullrakes; a method
that is normally used to harvest these resources in the bay. Rhode Island DEM
enforcement staff and the Department of Health will ensure that quahogs
harvested from the closed areas are transported to the sanctuary site and that
harvesting from the sanctuaries is prohibited until after the quahogs have
safely depurated.
Criteria Evaluation
Transplanting quahogs from closed areas to areas that are open to harvesting is a proven method of increasing
fishermen's access to an otherwise unharvestable resource. Spawner sanctuaries
have been used for a variety of species of fish and shellfish and have proven
successful for enhancing local populations of these species. This project will
compensate the public for the lost use of quahog beds during the oil spill. The
cost of moving the shellfish is relatively inexpensive. Shellfishermen are paid
a fee (usually $.10/lb) to harvest the shellfish to be transplanted. This
resource in turn is then made available to the public for harvesting.
C. Eelgrass bed restoration (Preferred Alternative)
Personnel from the National Marine Fisheries Service's (NMFS) Beaufort, North Carolina laboratory will transplant
eelgrass, Zostera marina, to approximately 10 different locations in
Narragansett Bay to enhance fishery habitat as a compensatory measure for lost
resources. Sites will be identified following site surveys and consultation
with local investigators, and selection will be based on water quality
conditions, sediment particle size, historical evidence of presence of
eelgrass, and degree of exposure to waves and tidal currents.
Eelgrass is an important component of the marine ecosystem. Eelgrass meadows serve several important functions including
stabilizing sediment, providing nursery areas for fish and shellfish, filtering
suspended particles and nutrients from the water column, and providing an
important source of organic matter to the ecosystem (Thayer, et al.,
1984). Eelgrass meadows serve as important habitats for forage fish and
numerous commercially and recreationally important marine fish and shellfish
including bay scallops (Argopecten irradians), quahogs, tautog (Tautoga
onitis), winter flounder (Pleuronectes americanus), and
sticklebacks. (Thayer et al., 1984, Heck et al. 1989, and
Peterson et al., 1984).
Eelgrass beds were drastically reduced throughout their range in North America and Europe, including Narragansett Bay
during the 1930s but have generally recovered since that time (Thayer et al.,
1984). However, in some areas, such as Narragansett Bay, recovery has been
limited (Kopp et al., 1995). The cause for the catastrophe, termed
"wasting disease," has been determined to be the protozoan Labyrinthula
zosterae (Muehlstein et al., 1991). More recently water quality
degradation has inhibited and caused the decline of seagrass in many locations
(Short et al., 1993). The loss of eelgrass has caused several severe
adverse impacts to the coastal ecosystem including coastal erosion, changes in
the sedimentary environment with concomitant changes in the benthos, and a near
complete disappearance of the bay scallop in some locations including
Narragansett Bay (Thayer et al., 1984).
While a complete recovery of eelgrass has not occurred in Narragansett Bay, remnant beds still persist in numerous
locations. Several reasons may have conspired to prevent greater recolonization
of eelgrass in the bay. When seagrass losses occurred during the wasting
disease of the 1930s substantial erosion of shorelines apparently occurred
(Dexter, 1944). Concomitant with this erosion, one would expect substantially
higher turbidity, a factor that reduces light availability and thus, potential
eelgrass habitat. Over several decades, it is likely that erosion and sediment
resuspension would have abated as an equilibrium between available, erodible
substrate and water motion developed. However, at this time, widespread coastal
development was on the rise which would have exacerbated turbidity, nutrient
loading, and epiphytization, all factors which have been shown to severely
limit the growth and survival of seagrass beds. Thus, dispersal from surviving
stocks may not have found suitable areas to colonize or were so chronically
disturbed that they could not form critical patch sizes to survive (Olesen and
Sand-Jensen, 1994).
Other factors, such as increased shellfish harvesting which disturbs the bottom, anchor damage, propeller scarring, all
could work together to create localized impediments to recolonization.
Moreover, seagrass restoration research has demonstrated that shortly after
transplanting seagrass, when the plants are at a low density (much like early
stage colonization), significant losses can be effected by bioturbation
(Fonseca pers. com., 1994). One vector of this disturbance in New England is
the European green crab. The advent of this introduced species may also have
limited the recolonization of the bay.
Given the importance of eelgrass to commercially and recreationally important marine resources and the marine ecosystem
as a whole, restoring this seagrass has been attempted in numerous locations
and transplanting techniques have been fairly well developed (Fonseca et al.,
1982, 1994; Fonseca, 1990, 1994). The historical existence and persistence of
eelgrass beds in Narragansett Bay provides the strongest evidence that
restoration of this seagrass in the bay is possible. In addition, with
continued and planned improvements in sewage treatment in the bay, water
quality is expected to continue to improve, thus enhancing conditions for the
survivability of eelgrass.
Personnel from the NMFS Beaufort lab will implement the proposed eelgrass restoration project jointly with the
University of Rhode Island's Graduate School of Oceanography and the Rhode
Island Department of Environmental Management's Narragansett Bay Project. With
funding provided by the World Prodigy settlement, the Rhode Island Aqua
Fund and the NOAA National Estuarine Research Reserve Program each institution
will contribute funds and expertise to accomplish the restoration of eelgrass
in the bay.
Methodology:
NOAA will select up to 10 locations throughout Narragansett Bay to transplant eelgrass. These sites will be selected
based on sediment type, water quality and clarity, wave energy, and human
activity. At each of the 10 planting sites six planting plots will be
established in a single block. Each plot will measure 5m x 5m. Each plot will
be caged to protect the plants from bioturbation. Each plot will consist of two
rows of five planting units (1-5 shoots per planting unit) each. One pair in
each plot will receive fertilizer at the time of planting. Total planting would
entail 1,000 to 3,000 plants spread over 540 square meters of seafloor.
Eelgrass plants will be harvested from existing beds in Ninigret Pond or other
suitable locations. Monitoring:
The objective of the monitoring efforts will be to determine the degree of success of establishing the eelgrass beds.
Specifically, monitoring to determine percent survival, areal coverage, number
of shoots per planting unit, and benthic colonization will be undertaken on a
regular basis for three to five years. Significant cost savings will be
realized by the joint monitoring efforts of NMFS, URI, and R.I. DEM.
Cost:
The costs for personnel, equipment, transplanting, travel, and monitoring is approximately $100,000.
Environmental Consequences
This alternative will alter the topography of the bottom. The added vegetation will alter the flow regime and function
to stabilize sediments. This will also increase the accumulation of organic and
inorganic materials and will reduce erosion as a result of sediments binding
with the roots (Fonseca, 1992; Kirkman, 1992). The added vegetation will have a
positive increase in the amount of detrital nutrients contributing to the food
web and will increase nursery areas for fish and shellfish (Fonseca, 1992;
Kirkman, 1992 ). The eelgrass plants to be used for transplanting will be
harvested in small patches from a healthy source bed in Ninigret Pond. It is
expected that the harvested areas will be rapidly recolonized.
Criteria Evaluation
The objective of this project is to establish a number of eelgrass beds throughout Narragansett Bay to provide habitat
for a variety of resources which were injured by the oil spill. While eelgrass
beds were not directly affected by the spill, resources that use this habitat
during their lifecycle were injured and will benefit from its restoration. The
literature documents successful techniques to establish seagrass beds and
provides information on the relative value of created or restored beds versus
natural beds. Costs to establish beds are relatively inexpensive, though
transplanting is labor-intensive. In addition, our URI partners in this project
will be examining other lower-cost techniques (seeding) to establish eelgrass
beds.
D. Sachuest Point Salt Marsh Restoration (Preferred Alternative)
Salt marsh ecosystems are among the most productive natural systems on earth and serve as spawning, feeding and nursery
areas for numerous species of fish and shellfish and as a valuable habitat for
shorebirds and waterfowl (Teal, 1986). Salt marshes also maintain water quality
by trapping sediment and pollution, provide flood and storm damage protection,
and recreation to the public. Salt marshes have also been subject to a wide
variety of development activities which have severely altered their diversity
and productivity. Along the New England coastline railroads, roads, and other
forms of development have often restricted the natural tidal flow into marsh
systems. As the natural hydrology of the salt marsh system changes and the
salinity is reduced the natural salt marsh vegetation (Spartina spp.)
begins to change (Roman et al., 1984; Roman et al., 1995). Often
common reed (Phragmites australis), an invasive brackish water plant,
will colonize such areas. Phragmites is thought to be of limited value
to fish and wildlife. Tidal restrictions also reduce the area of marsh
available to estuarine dependent fish and reduce the outflow of detrital
material from the marsh system.
The objective of this proposed alternative is to enhance estuarine fish habitat by restoring the natural salt marsh
vegetation and associated organisms to a portion of the Sachuest Point salt
marsh in Middletown, RI (Figure 4) as a compensatory action for lost resources.
As described earlier, numerous species of estuarine finfish larvae were injured
by the World Prodigy oil spill and this project is designed to restore
the losses of finfish and their associated habitat injured by the spill. The
marsh restoration will be accomplished by restoring tidal flushing to a portion
of the marsh where flow has been restricted.
The salt marsh within the Sachuest Point National Wildlife Refuge has been adversely affected by road construction and
an inadequately sized culvert that has severely reduced tidal flow into this
marsh. Tidal flow is the key factor for the health of a salt marsh. As a result
of the decrease in tidal flow, salinity has decreased and Phragmites has
colonized large areas of the marsh and reduced its value for fish and wildlife.
Other significant disturbances over time have adversely affected the salt marsh
system in the refuge, including two freshwater reservoirs which supply drinking
water to the City of Newport and a now closed and capped municipal landfill.
Both the reservoirs and landfill have eliminated large areas of former salt
marsh.
A number of recent studies of restoration projects suggest that reintroduction of tidal flow into
hydrologically-restricted marshes can restore a number of functions and values
of those marshes (Roman et al., 1984; Sinicrope et al., 1990;
Barrett and Niering, 1993; Peck et al., 1994). The reintroduction of
tidal flow into Phragmites-dominated marshes is based on the premise
that an increase in salinity and flooding will decrease and kill Phragmites
and allow natural recolonization of the marsh by Spartina spp. and other
salt marsh plants. Hellings and Gallagher (1992) found that P. australis
density, growth, and total above ground biomass decreased significantly with an
increase in salinity and flooding. In a project undertaken in Connecticut,
Bongiorno et al. (1984, cited in Marks et al., 1994) found that
with the restoration of tidal flow into a Phragmites dominated marsh, a
1- to 3-foot reduction in stem height resulted over each of three years. In
addition, plant density declined dramatically from 11.3 plants/m2 in 1980 to
3.3 plants/m2 the following year. In following years, P. australis continued
to decline, although less dramatically. In addition to the decreased height and
density of the Phragmites, typical marsh flora including Salicornia
(saltwort), Distichlis spicata (spikegrass), S. alterniflora (saltwater
cordgrass), and S. patens (salt meadow grass) returned (Marks et al.,
1994).
In a well studied case of salt marsh restoration in Connecticut, a number of studies have concluded that restoration of
tidal flow has had a dramatic impact on both the flora and fauna of the tidally
restricted portion of the marsh (Sinicrope et al. 1990; Barrett and
Niering, 1993; Allen et al., 1994; Peck et al., 1994). A central
creek flowing south through the marsh was impounded by a dike in the mid 1940s
to create waterfowl habitat. The impoundment converted the former salt marsh to
a cattail (Typha angustifolia) dominated brackish marsh. Tidal flushing
was restored to the area in 1978 and in 1982. Sinicrope et al. (1990)
found that Typha, which covered 74% of the transects in 1976, covered
only 16% in 1988, with most stunted. However, they found that Phragmites
cover increased from 6% to 17%, though 9% of the transect lengths had standing
dead Phragmites. The authors noted that this species was also relatively
depauperate. S. alterniflora showed a dramatic increase, from less than
1% in 1976 to 45% in 1988. A variety of other salt marsh species which were not
seen in 1976 covered an additional 20% in 1988. In addition, the authors
measured peat salinity which showed that Typha remained relatively
healthy at 10% or less, became stunted as the salinity increased and died at
about 20%. Phragmites grew best at 20% or less and by 30%, stands of
this species were extremely depauperate (0.3-1.0 m tall), and typical salt
marsh species tended to dominate.
The authors suggested that there may have been two reasons for an increase in Phragmites coverage. Herbicides
were used in the early to mid 1970s to control Phragmites and may have
skewed the baseline data. Secondly, Typha may have limited the spread of Phragmites
in 1976. Once tidal flow was restored, however, Typha declined rapidly
and allowed for the expansion of the more salt-tolerant Phragmites.
Average Phragmites height in 1976, however, was 2-3 m and was 0.3 to 1.5
m in 1988. Additionally, since the time of the study, it appears that Phragmites
has continuously decreased in coverage (Scott Warren, Connecticut College,
pers. comm.).
Fell et al. (1991) and Peck et al. (1994) studied the impact of the restoration of tidal flow in this same
system on invertebrate populations. Fell et al. (1991) compared
distribution and abundance of the high marsh snail (Melampus bidentatus)
above and below the impoundment dike. Peck et al. (1994) compared this
same species and the ribbed mussel (Geukensia demissa) above and below
the impoundment and also with a nearby reference marsh. These studies found
that populations of M. bidentatus, Geukensia and other tidal
marsh invertebrates were re-established on the restored portion of the marsh
system and no significant differences in the numbers of the snail were found.
Site Description
The Sachuest Point salt marsh is located in the Sachuest Point National Wildlife Refuge in Middletown, Rhode Island and
is bordered by Third Beach and the Sakonnet River to the west, Second Beach and
Sachuest Bay to the east, Gardiner Pond (drinking water reservoir) to the
north, and the upland Sachuest Point to the south (Figures 4 and 5). The
property is owned by the U.S. Fish and Wildlife Service. The salt marsh is fed
by a tidal creek which flows from the Sakonnet River through about 400 feet of
beach to a 5.5 foot diameter culvert under Third Beach Road. The tidal creek
flows through a relatively healthy salt marsh consisting of Spartina
alterniflora, S. patens, Distichlis spicata, and Juncus
gerardi (Area A on Figure 6). Just after the tidal creek passes through
the culvert, a smaller tidal channel branches off in a southerly direction
through the marsh. After some distance, this channel is crossed by a road which
connects Third Beach and Sachuest Point roads ("connector road"). The
channel, which has a maximum width of eight feet, carries tidal flow through a
20-inch culvert underneath the connector road to another pocket of wetlands
totaling 12.8 acres (Area B on Figure 6). The channel is silted in and has been
colonized by S. alterniflora some 250 feet before the channel reaches
the culvert. The culvert also appears to be clogged. Immediately south of the
connector road an area of salt marsh is present measuring about 1.8 acres in
area. The majority of the remainder of Area B (about 11 acres) contains common
reed and shrub wetland.
Fish and wildlife use at the site varies throughout the year. Bird nesting species found there include Willow
Flycatcher, common yellowthroat, Eastern phoebe, swamp and song sparrows,
yellow warbler and others (Table 1). Breeding bird surveys conducted since 1993
indicate that flycatchers, yellowthroats, phoebes, and both swamp and song
sparrows are the most abundant nesting species using the site (Table 1).
Table 1. Average number/survey of the ten most abundant songbirds at the proposed wetland restoration site (Point Count
site 2) and a nearby saltmarsh (Point Count site 1) at Sachuest Point National
Wildlife Refuge.
Species Average #s Site 1 Species Average #s Site 2
Song Sparrow 2 Willow Flycatcher 3.9 Common Yellowthroat 1.9 Barn Swallow 3.0 Red-winged Blackbird 1.6 Common
Yellowthroat 2.5 Yellow Warbler 1.4 Eastern Phoebe 1.3 Sharp-tailed Sparrow 0.7
Swamp Sparrow 1.1 Willow Flycatcher 0.6 Song Sparrow 1.1 Gray Catbird 0.5
American Robin 0.9 American Goldfinch 0.5 Brown-headed Cowbird 0.5 Mourning
Dove 0.4 Yellow Warbler 0.4 Northern Cardinal 0.3 Red-winged Blackbird 0.3
Information on wintering species of birds at the site is sketchy but probably includes black ducks, yellow-rumped
warblers, and white-throated sparrow. Wading birds such as rails and bitterns
might use the site infrequently but have not been observed. No data regarding
small mammals or reptiles exist for this area but probably include meadow vole,
short-tailed shrew, and Eastern garter snake as some of the more common
species. Fish species found in the tidal creeks include American eel (Anguilla
rostrata), striped killifish (Fundulus majalis), mummichog (Fundulus
heteroclitus), and Atlantic silversides (Menidia menidia) (J.
Catena, pers. obs.). The Rhode Island Division of Fish and Wildlife has a
permanent juvenile finfish sampling station just off Third Beach. The most
frequently sampled fish from 1987-1993 at this station include winter flounder
(Pleuronectes americanus), windowpane (Scophthalmus aquosus),
Atlantic silverside, mummichog, tautog (Tautoga onitis) and bluefish (Pomatomus
saltatrix) (RIDEM, unpublished data).
No state or federally threatened or endangered species are known to inhabit the immediate area. Sachuest Point is a
state historical site for Sea Beach Amaranth (Amaranthus pumilus) a
federally listed species. The federally endangered peregrine falcon sometimes
uses the Refuge for roosting or foraging during migration but none have been
observed at the site. Several "State Interest" species occur in the
area including great blue heron, snowy egret, great egret, and glossy ibis. All
species use the site for foraging and not nesting. Northern harriers (state
endangered) can also be found in the area during the winter and might use the
site for foraging only, but are listed only in terms of their nesting status.
No state-listed plants are known to occur at the site.
Proposed project description
Under the auspices of the Coastal America Partnership, the U.S. Army Corps of Engineers' New England Division (COE)
provided technical assistance to NOAA to develop recommendations for restoring
tidal flushing to the restricted marsh (U.S. Army Corps of Engineers, 1994).
The COE conducted a hydraulic analysis of the marsh system using data from a
limited elevation survey and tidal information gathered from NOAA's nearby
Newport, RI tidal gage. Based on this analysis, the COE recommended that
twin-30 inch culverts replace the existing 20-inch culvert beneath the road to
adequately restore tidal flushing to the marsh south of the connector road. In
addition, the channel feeding the culvert will be cleared of vegetation and
deepened approximately two feet. Without channel modification, hydraulic
scouring may occur through normal tidal flushing. However, the natural process
is expected to be significantly slower because of the amount of root mass and
silty material which must be removed. A channel south of the connecter road
will also be deepened and lengthened to extend the influence of the tidal flow
into the Phragmites dominated area of the marsh.
The combination of channel modification and placement of twin 30-inch culverts should increase tidal range within Area B
by 1.0 to 2.0 feet, providing slightly greater high tide elevations (a few
tenths of a foot) and significantly lower low tide elevations (approximately
one foot). The larger culvert will inherently provide better drainage during
low tide conditions. After flow is restored to Area B with larger sized
culverts, maintenance of the channel may not be required.
A baseline assessment of the marsh system will be conducted prior to culvert replacement to gather more detailed data on
vegetation, fish use, hydrology, and topography. The hydrologic and topographic
information will be used to verify the COE's recommendations and to develop an
accurate estimate of acreage expected to be influenced by the increased tidal
flow. Post-construction monitoring will be conducted every 3 years over a 10
year period to determine the success of estuarine fish habitat enhancement.
Specific monitoring elements will consist of rate of colonization by S.
alterniflora and other marsh plants, plant species composition, plant
cover and height, hydrology, soil salinity, and fish use of tidal creeks.
Costs
The costs for personnel, equipment, construction, baseline assessment, and monitoring is approximately $80,000.
Environmental Consequences
Marsh enhancement will have positive effects on floral and faunal species composition. It will create valuable nursery
grounds, allow for the reoccupation of salt marsh vegetation, and increase fish
use of the tidal creeks.
Based on the literature and past experiences in Connecticut and elsewhere, the restoration of tidal flow into area B
should convert the Phragmites-dominated marsh into a Spartina-dominated
system. Salinity and tidal range should increase and slowly allow for the
reoccupation by Spartina and other of salt marsh vegetation as the less
salt-tolerant P. australis dies out. Restoration of tidal flow should
also enhance the marsh as a habitat for fish and invertebrates that are
dependent upon salt marsh ecosystems by making more habitat available for them
to exploit. Bird communities should change to those more typical of the nearby
saltmarsh (area A). Sharp-tailed sparrows, marsh wrens, and red-winged
blackbirds which are typical of the marsh to the north of the connector road
(Table 1) should increase on the south side of the road as well when more
typical high marsh vegetation is established. Black duck use will probably
increase as Phragmites retreats from open water areas and wading bird
use will probably increase also.
It is quite likely that if no restoration activity occurs at this site, Phragmites would continue to colonize the
marsh. Available subtidal and intertidal habitat for fish and invertebrates
would continue to decline since access to the marsh by these organisms would
continue to be cut off. Phragmites coverage would likely would reduce
numbers of swamp sparrows, common yellowthroats and other wetland associated
species.
This alternative will have no effect on the cultural environment. Criteria Evaluation
The objective of this project is to enhance estuarine fish habitat by restoring the natural salt marsh vegetation and
associated organisms to a portion of the Sachuest Point salt marsh in
Middletown, RI. While this particular salt marsh was not injured by the spill,
resources that use salt marsh habitats during their lifecycle were injured and
will benefit from its restoration. Marsh restoration of this type is fairly
well documented (Roman et al., 1984; Sinicrope et al., 1990; Fell et
al., 1991; Barrett and Niering, 1993; Roman et al., 1995). The
cost of restoring tidal flow into the Sachuest Point marsh system is relatively
inexpensive given the resource benefits that will accrue. Furthermore,
cost-savings will be realized since the property is owned by the U.S. Fish and
Wildlife Service and equipment and personnel from that agency will be used in
carrying out certain aspects of the restoration project.
E. Construct and operate a hatchery (Not proposed)
The construction and operation of a shellfish and lobster hatchery is a potential method of replacing the biota impacted
by the spill as well as their lost progeny. The oil spill resulted in closure
of shellfish beds and mortality to larval quahogs and larval and adult lobsters
which the hatchery would attempt to replace. Enhancing natural population size
by the release of larvae or juveniles reared in hatcheries is a time tested
method for some freshwater and a few marine fish species. Hatchery stocking of
lobsters and quahogs has been used extensively. However, there has been minimal
evaluation of the impact of these stocking activities on the natural
populations of these species. For reasons discussed below the construction and
operation of a hatchery is not proposed.
Attempting to enhance natural quahog populations with hatchery-reared quahog seeds is a method that has been used
extensively. However, there effectiveness has never been adequately evaluated
(Malouf, 1985). Hatchery-reared quahog larvae dispersed into the bay are likely
to suffer high predation losses and their impact on local populations is likely
to be minimal. Research has shown that survival of quahog seed is greatly
affected by its size when introduced into the environment. The larger the seed
size the greater the likelihood of survival. However, because the space and
nutrient requirements increase geometrically with size, hatcheries typically
sell the seeds in the 2-4 mm size range. Using such a seed size increases risk
of predation, and reduces the probability of success. The probability of
survival increases when quahog seed is adequately protected by nets, screens,
or other protective measures (Kraeuter and Castagna, 1985; Castagna, 1984).
Even with protection and large seed sizes, however, predators can still cause
significant mortality (Flagg and Malouf, 1983). In addition, there is no
evidence that these introduced juveniles result in long-term enhancement of the
population (Malouf, 1985). An on-site hatchery program would provide the
necessary seed but would have to be maintained and operated indefinitely. In
addition, protected nursery and grow-out areas would be required to give the
hatchery-reared seed a chance to survive predation.
Early in this century, lobster hatcheries were very common in Canada and New England as well as France, Norway and
England and these hatcheries produced and released between 200,000 and one
million larvae each year (Addison and Bannister, 1994). However, the impact of
these releases never was evaluated adequately. Lobster hatcheries are rare now,
because the costs of larval rearing and release could not demonstrate benefits
to the fishery. Recently, a new technique to evaluate effectiveness of
hatcheries has been used. This technique involves rearing the lobsters to a
larger size (approximately three months old, 15mm carapace length) and tagging
them with coded, microwire tags before setting them out in appropriate natural
habitat (Addison and Bannister, 1994). The harvested lobsters are then scanned
for the presence of the coded tags. Rearing to this size is considerably more
expensive than rearing and releasing them at the traditional three to four week
stage (stage IV -- as is practiced at the Massachusetts State Lobster
Hatchery). The increased expense is due to the need to separate and rear each
juvenile lobster in individual containers after stage IV because of their
cannibalistic behavior.
Recent studies conducted in England indicate that hatchery-reared lobsters can recruit to the fishery. (Bannister et al.,
1994, Addison and Bannister, 1994). Nearly 50,000 three-month old
hatchery-reared lobsters were tagged with coded microwires and released into an
area that supports a substantial fishery (Bannister et al., 1994). Of
these, 621 were recaptured up to eight years later. The recapture rate of
tagged lobsters was about 1% of those released. However, when the data were
viewed as catch rate per size class, tagged lobsters made up a much higher
proportion (10 35%) of all lobsters of that size. Sampling outside the area of
seeding gave no evidence of dispersion any distance from the general release
area. Bannister et al. (1994) estimated that the survival rate from the
time of seeding to entry into the fishery (4-8 years depending on growth rate)
may have averaged 50%. Despite this, the tagged lobsters were a very small
proportion of the fishery catch, suggesting that seeding 50,000 three-month old
juveniles over a five year period did not make a substantial difference in
catch rates. An additional question remains as to whether the hatchery-reared
lobsters added to the natural stock or merely displaced it (Addison and
Banister, 1994.) The question of the economic benefit of re-stocking remains
open.
Although studies focusing on the introduction of stage X to XII hatchery-reared juveniles show there is initial
biological success, long-term enhancement of the fishery has not been shown.
With a low experimental recapture rate, it is difficult to determine if the
hatchery-reared lobsters that survived are beneficial to the natural population
or if they survived at the expense of the naturally existing lobster recruits.
It is uncertain if these stocks result in long-term population benefits. One
possibility is that hatchery-reared lobsters would need to be released in large
numbers to be able to impact a local fishery (Bannister et al., 1994).
Future studies will determine if hatchery-reared stocks enhance a natural
community or if they increase competition for shelter and displace the natural
population. If the introduced lobsters displace the natural population, then
what has resulted is not really an enhancement but a restocking. More research
is needed to determine effects on the genetic diversity of hatchery-reared
lobsters.
Cost
The construction and continuous operation of a hatchery requires funding beyond what is available from the oil spill
settlement and natural resources trustees are prohibited from selecting a
restoration project that would require funding beyond what is available (43 CFR
11.93(b)). Although the construction of a hatchery is a one-time expense,
operational expenses would exceed the available budget since the hatchery would
need to be operated in perpetuity to maintain the quahog and lobster
populations needed to sustain a fishery. Funding to operate a hatchery would
last less than five years with no guarantee that a self-sustaining natural
population would result. While the facility could be transferred to other
entities (state government or non-profit organization) NOAA has received no
commitments for such a transfer. Without such a commitment it would be
impractical to build and operate a hatchery for only a few years.
Environmental Consequences
Potential impacts of introducing hatchery-reared organisms into the environment include: introduction of disease
organisms or exotic species; reduction of genetic variability in stocks, or
masking of the total extinction of local natural stocks; and reduction in
growth and survival of natural and planted clams if the local environmental
carrying capacity is exceeded (Malouf, 1985). It is not known if
hatchery-reared lobsters enhance a natural population or if they increase
competition for shelter and displace a natural population. Long-term monitoring
studies are needed to determine the effects of introduced juveniles on wild
stocks. Although there may be initial biological success with introduced
lobsters, it is not known if this success is sustainable without continued
human intervention. Hatchery-reared juvenile lobsters artificially elevate the
natural population and more information is needed to determine the density
dependent factors controlling the balance in the ecosystem (Addison and
Bannister, 1994, Bannister et al., 1994).
There should be no effect on the cultural or historical environment of the Narragansett Bay area.
Criteria Evaluation
Lobster and shellfish hatcheries, while having been used quite extensively over the years, remain an unproven technique
to enhance populations of these species. New evaluation techniques have been
developed for lobsters. However, to employ these on a large scale would be
cost-prohibitive. Cost-effectiveness is quite low given the relatively high
cost of construction, operation, and maintenance of a hatchery and the lack of
proven success. In addition, available funding is insufficient to continue
operation of a hatchery beyond a very limited time period. Due to these
factors, hatchery construction and operation is not selected as a proposed
alternative.
F. Purchasing and seeding juvenile clams and lobsters (Not proposed)
A slight variation on the above alternative is to purchase larval clams and lobsters from existing hatcheries and
release them into the Narragansett Bay environment. Larval lobsters and clams
would be purchased from hatcheries currently operating in the area. The
juveniles would be transported to pre-selected sites and released. Sites would
be selected based upon habitat types, water quality, and circulation patterns.
While the expense of constructing and operating a hatchery would be saved, this
alternative has not been proven to enhance the populations of these species.
See the above hatchery alternative for further discussion. For these reasons,
this alternative is not proposed.
Cost
This alternative faces operating challenges similar to the hatchery because this program would need to be operated
indefinitely. With the funds available for restoration, operating this program
in perpetuity is not feasible.
Environmental Consequences
Effects under this alternative are similar to those described under the hatchery alternative since lobsters and quahogs
would be placed in the environment in the same manner as described above.
Please refer to the discussion of the effects on the biological environment
under the hatchery alternative. There would be no effect on the cultural
environment under this alternative.
Criteria Evaluation
Purchasing and seeding larval quahogs and lobsters on a scale adequate to enhance the population of Narragansett Bay is
not likely to be successful given the level of funding available (see McHugh,
1981). Methods to evaluate effectiveness of seeding have remained elusive until
relatively recently. However, the cost for implementing these evaluation
techniques described above would reduce the cost-effectiveness of the project
relative to the other available alternatives. Given the uncertainty of the
relative success of enhancing lobster and quahog populations using the seeding
technique, this alternative is not proposed.
G. Quahog habitat enhancement by shelling (Not proposed)
Another potential option to enhance quahog populations in the bay is to select one or more sites for
"shelling" the bottom ("cultching") by broadcasting bivalve
shell over the bottom. This option is based on studies which indicate that
quahogs are more abundant in areas with a naturally high percentage of shell on
the bottom (Pratt, 1953; Wells, 1957; Saila, et al., 1967; Craig and
Bright, 1986; Kassner et al. 1991). This method, however, was rejected
because, while shelling can enhance the bottom for a variety of organisms, it
is still largely experimental for quahogs with unproven, though potentially
promising, results (Kraeuter et al. 1994, Kassner, 1995).
Like many forms of marine life, quahogs spend the earliest portion of their life cycle as free floating planktonic
larvae and then make the transition to bottom-dwelling life up to two weeks
after fertilization. It is during these early stages that quahogs are most
heavily preyed upon. Rice (1992) indicates that the period of larval settlement
and metamorphosis is one of the most critical in the quahog's life cycle and
large numbers of larvae do not survive the transition. Preferred settlement
locations appear to be important for minimizing subsequent post-settlement
predation losses. One potential approach to enhancing quahog populations is to
improve the survival rate of juveniles through the provision of shelter from
predators by shelling the bay bottom.
Cultching has been used to expand shellfish resources, in particular oysters, in the United States and in other
countries. Several states encourage habitat enhancement with cultch.
Connecticut has an active program to enhance oyster beds that has resulted in
the placement of more than four million bushels of cultch on public shellfish
beds (Volk, 1992). The State's effort has resulted in both a sustained growth
in the number of active oyster harvesters and increased stocks of harvestable
resources on the public beds (Volk, personal communications). Within the
borders of Rhode Island, cultching of oysters beds was once a traditional
practice. The decline of the oyster industry as a result of overfishing,
hurricanes, disease, increased predation and pollution in the 1960's and the
associated reduction in shucking operations providing suitable cultch precluded
its continuation.
The methodology would involve dispersal of clean shell over the bay bottom from the deck of a barge, using a high
pressure water jet or other dispersive technique. Cultching would take place in
12 to 20 feet of water (Mean Low Water). A density of 2,000 bushels per acre
(Tallmadge Brothers Company, personal communications) for creating shellfish
setting habitat on stable, sandy to gravelly bottoms would be targeted. This
amount would allow the shells to form a uniform, single layer. The shelled
bottom should enhance setting of juvenile clams and protect them from predation
by permitting the larvae access to the actual sediments while requiring
predators to move the shells in order to feed on the quahogs.
Monitoring activities would involve gathering pre- and post-cultching data, relative to quahog abundance and growth,
sediment characteristics, and topography. The data could include numbers of
quahogs per square meter, mass, and the comparison of those values to
pre-enhancement and adjacent site values. Control sites would be sufficiently
removed from the area to ensure that they are not within the zone of influence
of the cultching. The number of individuals settling into an area and their
survival ratio would be determined by count.
Cost
Shell would have to be purchased and transported to selected sites by tug and barge. Additional equipment costs would
include water-jet dispersal equipment to disperse shell over the bottom and
divers to insure proper placement. Shell could be purchased, transported and
dispersed for about $.70/bushel to $1.30/bushel or $1,000 to $3,000 per acre.
Monitoring costs to evaluate effectiveness of the project would add additional
costs.
Environmental Consequences
The alternative would slightly change the bottom topography of the area selected for cultching which in turn may
slightly change the hydrographic conditions along the bottom. The shell will
add three dimensional relief. Shelling could enhance other benthic dwelling
organisms such as crepidula (Crepidula fornicata), crabs, drills, and
other epifauna. No additional effects to the physical environment are expected.
This alternative will have no effect on the cultural environment.
Criteria Evaluation
Although the use of shell placement to enhance oyster survival is a proven technique it has only been attempted on an
experimental basis for the enhancement of quahogs (Kassner et al., 1991;
Kraeuter et al., 1994; Kassner, 1995). Given the uncertainties about
shelling's potential for success for enhancing quahog habitat this method was
not selected to address the injuries to the quahog resources caused by the World
Prodigy oil spill.
2. Habitat Acquisition (Not proposed)
One method to "restore, replace, or acquire the equivalent of the injured natural resources" is to purchase
coastal habitats, thus protecting them from further development and
degradation. While acquisition protects habitats from future development, it
does not restore injured resources directly. Rather it would provide
compensation for lost resources and services. Lands in the lower Narragansett
Bay would be targeted for purchase and turned over to state and local agencies
for ownership and management. For reasons discussed below habitat acquisition
was not chosen as a preferred alternative.
Habitat acquisition is often used as an effective coastal resource protection mechanism. However, except for small,
non-tidal wetlands, acquisition is generally seen as an unlikely solution for
conserving most of the remaining unprotected coastal wetland areas in the Rhode
Island area watersheds. There are several reasons for this. First, the federal
government already owns most of the remaining large, undeveloped coastal
wetlands in the state, and administers these areas as wildlife refuges.
Secondly, other entities, including governments and private conservation
groups, own and protect many other small to medium sized wetland areas
throughout the Rhode Island coastal zone. Thirdly, the State's public trust and
regulatory authority over all tidally influenced areas provides protection from
most potential non-natural threats to coastal wetlands. Finally, acquisition is
by far the costliest protection measure available. Land prices in the area are
prohibitively expensive because of their natural beauty and recreational uses.
In 1991, the price of coastal land was approximately $500,000 per acre. The
limited funds available to NOAA from the World Prodigy settlement
prevent the acquisition of coastal real estate large enough to provide
sufficient ecological services to mitigate for the impacts of the incident.
Cost
The cost of acquiring land is prohibitively expensive (see above).
Environmental Consequences
This alternative will protect acquired coastal wetlands from further on-site anthropogenic degradation. Natural
degradation or effects from off-site contamination will not be avoided. The act
of acquiring land will have no significant impact on the physical environment.
However, land acquisition will prevent future development activities on the
parcel in question and will have a beneficial impact on the physical
environment. Acquisition of land is not expected to have any negative impact on
the cultural environment. On the contrary, it is possible that parcels of land
may be selected to protect important historical or cultural resources.
Criteria Evaluation
Land acquisition in the Narragansett Bay area is not a cost-effective method to restore the injured resources given the
high per-acre cost of waterfront or wetland property. While acquisition is an
acceptable method to "acquire the equivalent of the injured
resources" it is NOAA's least preferred alternative if other direct
restoration alternatives are available. Furthermore, land acquisition would not
meet the goal of enhancing habitat value for a variety of marine resources with
specific emphasis on quahogs (hard clams), lobsters, and estuarine finfish. Due
to these factors, land acquisition is not selected as a proposed alternative.
3. No Action (Not proposed)
The no action alternative (i.e., natural recovery) allows biological impacts to be naturally mitigated. In order for
natural recovery to be selected as a preferred alternative, in addition to the
criteria mentioned above, all of the conditions listed below must be met: (1)
the natural process must be more effective in restoring the environment than
available or potential restoration options and alternatives; (2) the time to
recovery must not be significantly different from that resulting from human
intervention; (3) the affected area will not suffer from additional adverse
ecological effects before the site returns to a natural state; (4) no negative
threats to the health and safety of the general public will be caused by the
time lag of natural recovery; (5) funds are not available for restoration.
Cost
While immediate costs under the no action alternative may appear insignificant, the costs of the public's lost use of
the injured resources and their progeny must be considered. Planning,
permitting and construction costs would be avoided, but costs for monitoring
would be required to demonstrate that recovery has occurred.
Environmental Consequences/Criteria Evaluation
The no action alternative will not be effective in compensating the public for the injured and lost resources and
services. The resources that were killed or injured by the spill have been lost
and can no longer contribute to the productivity of the bay system. The no
action alternative will not replace those lost resources and services. There is
some evidence that even after 20 years residue from oil spills may remain
buried in sediments, and the sub-lethal toxic effects of the component parts
remain (Teal et al., 1992). At this time, it is likely that most of the
oil from the World Prodigy spill has been dispersed or buried and there
are no longer continuing effects from the oil. However, it is likely that oil
remained in beach sediments of the most heavily oiled locations for as many as
five years after the spill (Mulhare and Therrien 1993). In any case, the losses
sustained by the spill will not be recovered under this action. 4. Summary
Table II below summarizes the results of the criteria evaluation for each alternative. Each alternative was evaluated
based on the following criteria: (1) the project must restore resources injured
by the spill; (2) the project must be cost effective; and (3) the project
should use a proven technique and have a relatively high probability of
achieving the restoration goal. Those projects which could not satisfy all of
those criteria were eliminated from consideration. Based on the criteria
evaluation and the information provided in the above sections, NOAA has
determined that the following proposed actions will be the most effective means
to restore the injured resources: (1) enhance lobster habitat by establishing
several lobster reefs; (2) transplant quahogs and establish "spawner
sanctuaries" to help restock formerly productive areas of the bay and to
make more of the resource available to shellfishermen; (3) establish eelgrass
beds in multiple sites throughout Narragansett Bay to enhance fisheries
habitat; and (4) restore a saltmarsh system on Sachuest Point to enhance
habitat for estuarine dependent fish and shellfish.
| Table II - Criteria Evaluation |
Criteria |
|
Alternatives |
Restore injured resources or services |
Cost effective |
Proven technique |
| *Lobster reef |
+ |
+ |
+ |
| *Quahog spawner sanctuary |
+ |
+ |
+ |
| *Eelgrass restoration |
+ |
+ |
+ |
| *Salt marsh restoration |
+ |
+ |
+ |
| Habitat acquisition |
- |
- |
- |
| Lobster and shellfish hatchery |
-/? |
- |
- |
| Purchase and seed clams and lobster larvae |
-/? |
- |
- |
| Shelling |
+/? |
+/? |
- |
| No action |
- |
- |
N/A |
Key: + meets criterion, - does not meet criterion, ? uncertain, N/A not
applicable, *Proposed actions IV. BUDGET SUMMARY
Estimated costs for each of the proposed actions is provided below. Detailed
information on the budgets of each project is available from NOAA from the
contact person listed on the front cover page. "Project oversight,
administration and contingency fund" costs include personnel time for
developing the restoration plan, designing the restoration projects, issuing
contracts and grants to entities carrying out the specific projects, securing
permits, oversight of the implementation of each project, development of
outreach and educational material on the results of the restoration projects,
and additional funds for any unexpected future project-related expenses.
Lobster reef project: $270,000 Eelgrass bed restoration $100,000 Sachuest Point
salt marsh restoration $80,000 Quahog transplant and spawner sanctuary $75,000
Project oversight, administration and contingency fund $42,299
Total $567,299
V. FIGURES VI. FINDING OF NO SIGNIFICANT IMPACT
Finding of No Significant Impact
Having reviewed the attached environmental assessment and the available information relative to the proposed action in
Narragansett Bay, Rhode Island I have determined that there will be no
significant environmental impacts from the proposed actions. Accordingly,
preparation of an environmental impact statement on these issues is not
required by Section 102 (2) (c) of the National Environmental Policy Act or its
implementing regulations.
Rolland A. Schmitten Assistant Administrator for Fisheries National Marine
Fisheries Service National Oceanic and Atmospheric Administration
VII. LIST OF PREPARERS
John Catena Restoration Center National Marine Fisheries Service One Blackburn Drive Gloucester, MA 01930 (508) 281-9251
Elizabeth Shea, Gregory Miller Restoration Center National Marine Fisheries Service 1315 East West Highway Silver
Spring, MD 20910 (301) 713-0174
We would also like to acknowledge the contributions and assistance provided
by Mark Fonseca and Gordon Thayer, National Marine Fisheries Service, Beaufort,
NC, James Thomas, National Marine Fisheries Service, Silver Spring, MD,
Stanley Cobb and Kathy Castro, University of Rhode Island, Rick Wahle, Bigelow
Laboratory for Ocean Sciences, Larry Oliver and Bill Hubbard U.S. Army Corps
of Engineers, and Charles Roman, National Biological Service.
VIII. LITERATURE CITED
Adamowicz, S.C. 1994. "Restoring Greenwich Bay, Rhode Island: A Dynamic Partnership Approach to Nonpoint
Pollution Control in an Estuarine Embayment." In Conference Materials from
Coastal Nonpoint Source Workshop: Building Partnerships. October 17-19, 1994,
Tampa, FL.
Addison, J.T., and R.C.A. Bannister. 1994. "Re-stocking and enhancement of clawed lobsters: a review." Crustac
eana 67(2): 131 155.
Addison, J.T., R.C.A. Bannister, and S.R.J. Lovewell. In Press. "Variation and persistence of pre recruit catch
rates of Homar us gamma rus in Bridlin gton Bay, England. Crustac eana.
Bannister, R.C.A., J.T. Addison, and S.R.J. Lovewell. 1994. "Growth,
movement, recapture rate and survival of hatchery-reared lobsters (Homarus
gammarus, Linnaeus, 1758) Released into the Wild on the English East
Coast." Crustaceana 67(2): 156-182.
Barrett, N.E., and W.A. Niering. 1993. Tidal marsh restoration: trends in vegetation change using a geographical
information system (GIS). Restoration Ecology 1:18-28.
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