Oyster Reef Restoration and Monitoring
Restoration of Oyster Reefs for fisheries, habitat, and erosion control in North Carolina
(funded through the American Restoration and Recovery Act in collaboration with the NC Division of Marine Fisheries, North Carolina Coastal Federation, and North Caroline State University)
Oysters influence surrounding habitats through a variety ecosystem interactions, providing habitat and refuge for associated finfish and crustacean,filtration, and stabilization of surrounding substrates and protection to eroding marsh habitat in moderately wave energy environments. As part of the overall oyster restoration effort in NC, a novel approach in the southern region will utilize local watermen to place settlement material in shallow water habitats that are likely to catch oyster spat. Many of these areas are also exposed to moderate amounts of wave energy with subsequent erosion of tideflat and marsh edge. As part of this effort a minimum of four oyster reef restoration sites, each containing restored oyster reefs of various sizes representing different size scales (representing varying amounts of shoreline protection), were established along shorelines experiencing moderate erosion. All sites were monitored for aspects of ecosystem function, including erosion control, habitat addition, and fishery function as will adjacent reference habitats at each site.
Representatives from UNCW and colleagues at NOAA’s Beaufort Laboratory assessed the initial success of these oyster plantings by monitoring the development of oyster demographic data (settlement, size distribution, condition index) and utilization by associated fauna, at targeted oyster restoration sites and monitored the benefits that these restorations had on faunal utilization of adjacent shoreline areas. The successful establishment of healthy oyster reefs provides a self-sustaining biogenic structure capable of adjusting to sea level change, which will provide protection to the adjacent shoreline over a decade + timescale as well as providing a harvestable resource and enhanced filtration capacity.
The original goal of the this project was to follow reef development at two designated sites over an 18 month period starting with pre site characteristics in 2010 and following reef development at quarterly intervals through 2011-2012. Stabilization of substrate and protection of eroding marsh edge was assessed at the pre-construction phase and at the end of the project 18 months later. Other metrics of marsh development that were monitored included sediment characteristics, slope, mapping of shoreline edge, and plant stem density.
Ecosystem function of Oyster Shoreline Stabilization Projects: Efficacy and Support of local fishery
(NC Division of Marine Fisheries CRFL support)
Coastal areas of the United States are experiencing dramatic population growth. This growth produces impacts through direct and indirect mechanisms to both coastal habitats and fisheries. Coastal erosion is one of the most significant impacts directly affecting developed upland areas and degrading critical habitat. One approach that has been increasingly applied, for protecting shorelines, is the placement of oyster shell to establish protective reefs. This approach coincides with increasing interest in oyster restoration for ecosystem function along the Atlantic and Gulf coasts. However, there have been only limited studies monitoring the success of oyster shell plantings in reducing marsh loss, examining the conditions where this may be most feasible, and few efforts have attempted to quantify the ecosystem benefits. Previous work has shown the initial benefit of placing oyster reefs in front of marsh but has not addressed longevity and ecosystem services provided by these structures. With increased emphasis on providing methods to protect shoreline, reduce costs, and restore ecosystem function it is imperative the scientific community provide values for the contribution provided by these structures. This study will provide information on both the feasibility of using this approach in moderate erosion and the ecosystem service contribution in the process. This study will focus on specific parameters of oyster health and condition the ecosystem benefit from oysters as stabilization. The overall objective of this project is to provide scientific data on critical ecosystem services provided by shoreline stabilization techniques that utilize the placement of oyster shell (bagged and/or unbagged shell) to protect marsh shoreline. Specifically we will 1) compare key ecosystem parameters among established and newly developed shoreline stabilization projects, 2)Assess metrics of success in shoreline stabilization, and 3) Assess key ecosystem parameters including oyster and epifauna populations and level of primary producer biomass directly associated with oyster habitat among shoreline stabilization projects.
Dredging and Trawling Impacts
With the decline of oyster (Crassostrea virginica) populations through much of the East Coast of the United States, including some areas in North Carolina waters, efforts to conserve, enhance, and restore oyster populations have increased with mixed success. North Carolina maintains an active fishery, although declines here follow similar patterns to those described for the Chesapeake Bay and other areas. Much of the focus in oyster rehabilitation and enhancement has focused on the placement of cultch material to enhance settlement habitat for larvae, especially in the Northern and Central fisheries regions of the state where oysters have a predominantly restricted to the subtidal habitats. Oysters that grow in areas greater than 8 ft depth are generally harvested with a bottom dredge. This practice is effective for harvesting oysters but has in some cases been implicated as a contributing factor in the overall decline of oyster populations in many areas. Evidence suggests that in many instances dredging activities remove substrate from the reef and over time reduce the vertical relief of the reefs. Because many of the oyster growing areas suffering from declining populations also suffer from declining water quality and are subject to periodic hypoxic events the amount of vertical relief for a given oyster reef is critical to the long-term survival of subtidal oyster populations. The Division of Marine Fisheries (DMF) is faced with a particularly difficult problem in balancing the needs of an active commercial fishing industry and the rehabilitation/ enhancement of the existing oyster stocks. The current regulations allowed the use of a dredge up to100 pounds and no limit on the tooth bar length. The proposed changes at the time of the study would restrict the weight limit on dredges used inside the bays to 50 pounds with a tooth bar length no greater than 36 inches. The suggested gear restrictions were developed in consultation with former commercial fishermen who believe the heavier (100 pound) dredge weight would do a greater amount of damage to both natural reefs and cultch planting reefs compared to the lighter dredge. Opposition to the gear restrictions are based primarily on the belief (stated by several active commercial fishermen that) that the lighter weight dredge (50 pound) would not maintain contact with the substrate surface and would require greater tow times and greater numbers of tows per trip day to catch bag limits of oysters. The increased tow time and duration where thought to be a potential source of increased damage to the existing natural reefs and cultch plantings. This study compared the harvest efficiency of the each of two gear types in a side by side comparison, evaluating volume of substrate collected per bushel harvested, catch per unit effort, and overall time to harvest bag limit.
Habitat Function Study
Project summary coming soon!
To Seed or not to Seed (oyster reefs)
This NC Sea Grant funded project examines the efficacy and feasibility of using spat on shell to promote oyster reef development in the establishment phase of reef restoration. For the purposes of this study oyster shell mound reefs were established in intertidal habitats. All reefs were created using clean, cured loose oyster shell. A subset of these reefs received a “top dressing” of oyster shell with spat already settled, while the rest of the reefs received a “top dressing” of clean shells without spat settlement.
Benthic Research in the New Hanover Co Tidal Creeks
In New Hanover county tidal creeks efforts of the last few years have focused on describing the conditions of the oyster habitat within the various creeks and assessing habitat function of the oysters. Several studies have looked at aspects of physical structure (% shell cover, live vs dead, average shell height, and size demography) of natural and created reefs as it relates to the faunal community associated with the various oyster reef structures (low vertical relief reefs, reefs with high vertical complexity, small and large fragmented reefs). In this years effort we propose to build on the results of previous tidal creek studies as well as results of studies sponsored by NC Sea Grant and the NC Fisheries resource Grant program. Based on what we know of oyster densities and general oyster habitat area within the New Hanover County tidal creek systems we propose to target Hewletts and Pages creeks to continue surveys of oyster stock structure including, live oyster density, size demography, percent shell cover, associated fauna, and reef complexity and correlate this information with oyster health characteristics such as soft tissue biomass, reproductive condition, and disease incidence (time permitting).
Statewide Oyster Spat Monitoring Project
The Eastern Oyster (Crassostrea virginica) represents a critical species in estuarine systems throughout the Mid-Atlantic and Gulf coasts of the United States (Lenihan and Peterson 1998, Coen et al 1999, Grabowski 2002, and Stunz et al 2010). When considering essential ecosystem services, there are few analogs to oysters throughout their range. The decline of the oyster from historic peaks (MacKenzie 1996 and Frankenberg 1995) has prompted relatively large scale efforts to plant cultch to enhance oyster settlement with a specific goal of enhancing harvests. However, over the last decade new efforts to restore oyster populations have begun to focus on restoration of specific ecosystem functions. With this targeted approach to restoration a number of grassroots conservation organizations have developed community restoration groups involved in restoration on the local level. It is the recent emergence (and proliferation) of these groups throughout coastal NC that prompted the development of this volunteer based oyster spat monitoring project. Regardless of the goal of the restoration effort, an understanding of the local ambient settlement and inter-annual variation in that settlement is key to the long term success of any restoration project. For this reason UNCW’s Benthic Ecology Laboratory partnered with NC Sea Grant and local residents to form the NC statewide oyster spat monitoring program (SOSM) in 2007. This volunteer based program collects data on the monthly settlement of oyster larvae (and associated fauna) throughout coastal NC, addressing the need for data on oyster settlement established in the state’s oyster fishery management plan (FMP) (ncoystermonitoring.org). The most recent oyster FMP and the oyster rehabilitation plan (produced by North Carolina Division of Marine Fisheries (NCDMF)) indicated the need to provide suitable settlement substrate while oyster larvae are in the water column and competent to settle.
Since its inception SOSM has collected data from 70 sites across coastal NC. These sites have been maintained by over 117 volunteer including 6 school groups and 1 “home school” science outreach program. Since 2007 this program has been highly successful in gathering data and maintaining volunteer presence. A recent internal review of the program has indicated 2 areas that need improvement: 1) sparse data coverage in the northern and Pamlico regions, and 2) a need to improve the current data visualization tool. Specifically, potential users would like to see better data descriptors (metadata) and the ability to download data that is described graphically. The current study deals primarily with the second objective to provide easier access and clear descriptions of the data being collected. Here we will enhance the current data visualization by providing the ability to view records on a coast wide, regional as well as temporal basis. We will also provide the ability to download data on a regional basis to assist various user groups, including shellfish growers, DMF, restoration groups, and academia.
Marsh Benthic Communities and Restoration
Sustainable Estuarine Shoreline Stabilization: Research, Education, and Public Policy in North Carolina
(Funded through CICEET)
Summary coming soon!
Poplar Island represents nearly ~1700 acres of restored marsh habitat utilizing clean dredge material that would otherwise require disposal. The restoration of a suite of ecosystem functions is one of the primary factors determining the long-term success of this marsh restoration. This project has two components:
1) Evaluation of the infaunal assemblages in both restored and reference marshes at the Poplar Island restoration site and,
2) Evaluation of key factors of abundance and condition of Fundulus heteroclitus, as well as the nekton community composition between restored and reference salt marshes at the Poplar Island restoration site.
Infaunal samples were collected from both restored and reference marshes in 2012 while nekton samples were collected at key locations in 2013. The nekton evaluation portion of the project seeks to evaluate key factors of ecosystem health related to the abundance and condition of Fundulus heteroclitus, as well as the nekton community composition between restored and reference salt marshes as indicated by the Poplar Island Environmental Restoration Project (PIERP) in Chesapeake Bay. This project targets the nekton present at key sites (Cells 1A and 3D) and associated reference sites (Cabin Creek and Front Creek), which have previously been assessed for infaunal community composition. The nekton community will be collected during three key seasonal periods of spring, summer, and fall to better understand recruitment and demographic changes. This research concentrates on key indicator marsh resident species, Fundulus heteroclitus to evaluate marsh ecosystem function.
Effects of Erosion Control Structures on Adjacent Benthic and Nektonic Communities
Our research will provide information on the ecological impacts of the 3 most commonly employed erosion control structures: bulkheads, revetments and sills. Only limited information is available comparing bulkhead and control sites and much of this work has been plagued by low site replication, comparisons among sites that differ in multiple factors, and lack of sampling encompassing seasonal or interannual variations. Little information is available in the peer-reviewed literature on the influence of revetments in estuarine environments and no studies have examined communities on the seaward face of sill structures. Our study will be among the first to rigorously test the biotic impacts of all three structure types. The overall objective of this research is to understand how placement of erosion control structures affects adjacent benthic and nektonic communities. Emphasis is on examining structures established sufficiently long to have recovered from initial construction impacts, but newly established structures also will be examined to assess some of these short-term impacts. Specific objectives include:
- Compare selected infauna, epifauna and nekton communities between shoreline areas with bulkheads and control areas with similar land use and physical characteristics but lacking bulkhead structures.
- Compare communities between revetments and control sites with similar land use patterns.
- Compare communities between sill/marsh structures and control areas with similar land use.
- Compare the magnitude and direction of differences among structures and paired control areas.
- Observe short-term community responses to newly constructed structures relative to control areas.
Aquaculture of Shellfish, including Polyculture
Aquaculture Siting Tool (for Shellfish Aquaculture)
Shellfish aquaculture in North Carolina represents a small, yet important industry to the coastal counties, providing locally grown clams and oysters. Despite an increase in the demand for safe and sustainable seafood, including that of the local foods movement, the shellfish aquaculture industry remains relatively stagnant. While no single issue appears to have limited the growth of the industry, current growers and interested parties have suggested the following causes; difficulty in obtaining a lease, trouble identifying suitable growing areas including issues with closed water bodies due to water quality concerns or moratoriums, concerns regarding operational start-up costs, potential conflicts with other user groups, including potential theft, lack of knowledge about the industry, and the idea that “commercial fishermen do not want to be farmers.” It is very likely that a number of these concerns combined have contributed to the lack of increase in shellfish aquaculture operations and/or production. Therefore, utilizing a multidisciplinary approach, we aim to assess the state of the current shellfish aquaculture industry, identifying areas of concern for focusing extension efforts, develop tools to assist the siting of new or expanding shellfish operations and in identifying the economic constraints involving those facilities, evaluate the potential impact that growth of shellfish aquaculture could have on specific areas (particularly those areas historically dominated by commercial fishing), and lastly provide these tools to existing and potential growers through coastal workshops and demonstrations. To accomplish these goals, we intend to: 1) conduct a survey of shellfish aquaculture in all NC coastal counties to identify total production by species and type of production, sales of shellfish by species and size, market value of cultured product, seed sources, future production, and constraints to production, 2) using GIS, we will develop risk assessment maps for siting aquaculture facilities in several NC water bodies, accounting for parameters such as salinity, bathymetry, surrounding land use, and distance to water closed for shellfish harvest, 3) develop spreadsheet applications to analyze the inputs and outputs of shellfish aquaculture operations including changes in production, market price, and scale of operation, 4) using the spreadsheet data provided, determine the economic impact on local economies with the addition of new shellfish facilities and/or increase in production on existing leasing, and lastly 5) through a series of workshops/demonstrations (minimum of 5), we will work with NC Division of Marine Fisheries, NC Shellfish Growers Association, and current and potential shellfish growers to distribute the developed “tools” and assist in applying them to the fishery.
Identification of potential interactions between rack and cage shellfish culture and adjacent critical habitat (i.e. seagrass)
Based on the current conditions of many fishery species and projections for the next 2 decades NOAA Aquaculture estimates that nearly ~30% of seafood products currently consumed in the United States need to be replaced with aquaculture sources. Shellfish culture in the United States takes a variety of forms (e.g. direct grow-out, rack and cage, floating cages to names a few). According to the US Dept. of Agriculture, shellfish culture in the U.S. is worth ~$243 million annually. North Carolina shellfish culture has been relatively constant over the last decade, with the acreage of bottom leased in North Carolina largely unchanged over the last 5-7 years. One of the greatest concerns expressed by shellfish growers is declining water quality and the associated changes in water body classification (Turano et al. 2011). As water quality conditions deteriorate on a statewide level the amount of “leasable bottom” for shellfish culture is reduced. Many of the waterways, sounds, and coastal embayments of North Carolina support a variety of competing uses including both recreational and commercial activities (including but not limited to; recreational fishing, crab potting, commercial trawl and fixed net operations, recreational boating, and commercial transport) that further limit the acreage available for potential shellfish operations. In addition to competing uses there are also habitat types, such as sea grass species, that might also limit the amount of available area for shellfish operations. Here we propose to investigate the potential interactions between use of off bottom oyster grow-out technique and the growth/coverage of seagrass (SAV) species in targeted areas of NC. Currently bottom areas cannot be leased for shellfish culture if seagrass is present. The primary concerns are alterations to sediment and potential shading due to the placement of grow-out containers, however there are a series of shellfish ecosystem services with potential positive interactions on seagrass (Booth and Heck 2009). Experimental grow-out plots using the rack and cage system will be used to simulate oyster aquaculture to evaluate potential impacts on seagrass growth, shoot density, and shoot height.
Development of polyculture techniques in North Carolina coastal waters
Here we investigated the feasibility of growing both hard clams (Mercenaria mercenaria) and oysters (Crassostrea virginica) in a true polyculture system. There are a number of articles that focus on the culture of C. virginica under a variety of conditions in both intertidal and subtidal environments but information is more limited for the hard clam. While polyculture of hard clams and oysters has been tried in other systems there is no data in the literature on the feasibility and/or performance of hard clams grown in an intertidal/shallow subtidal polyculture system. North Carolina has a variety of potential grow-out habitats. Here we will grow hard clams at 4 sites that represent an important subset of potential aquaculture habitats. The condition(s) at these sites represent a variety of common situations including sea grass, high energy high salinity and emergent tide flats.
Project objectives were
- Compare hard clam performance among commonly used grow-out techniques such as open culture, use of predator exclusion meshes and grow-out in conjunction with rack and cage oyster culture.
- Compare hard clam performance using commonly used grow-out techniques and polyculture at a high salinity active shellfish grow-out area adjacent to Topsail Inlet.
- Compare hard clam performance using commonly used grow-out techniques and in polyculture with oysters at the UNCW research lease (this area was previously used for both commercial culture of both oysters and hard clams).
- Compare hard clam performance using common grow-out techniques and in polyculture with oysters at a shallow subtidal site in the central region with healthy seagrass population. At this site an assessment will be made of culture impact on seagrass density and height.
- Compare hard clam performance using commonly used grow-out techniques and polyculture with oysters in a coastal tidal creek estuary, Hewletts Creek.
Functionality of Lower Cape Fear River
River Monitoring (Part of the Lower Cape Fear River Program)
This project is a partnership with regional industry located on the Cape Fear River, state regulators and the UNCW. In 1995, this project was developed out of a need to acquire accurate data on the water quality and biological components of the lower Cape Fear River estuary. The water quality component of this project collected monthly data at 37 stations throughout the lower Cape Fear River covering ~ 30miles of the lower Cape Fear River and its major tributaries. The infuanal component of this program focuses on establishing long term datasets at 4 stations in the lower. These stations represent the both mesohaline and oligohaline regions of the estuary (a 5th station was added to the sampling regime in the more marine portion of the estuary as part of a separate effort). This project has shown clear indications of ecosystem level impacts from large perturbations (drought and hurricanes).
River Widening Project
Project summary coming soon!
CORMP Cape Fear River Plume study
The Coastal Ocean Research and Monitoring Program is a regional coastal ocean observing program that is primarily a remote observing network for the coastal ocean of southeastern NC and portions of SC. As part of this observing program a fisheries focused research based sampling program was implemented in the early 2000’s that supported sampling activities only. As part of this effort groups were able to sample and archive fisheries based samples for use in determining potential impacts and changes associated with shifting conditions in the coastal ocean environment.
Other Projects of Importance
Sea Grant Beach Functionality Study
When dealing with sea level rise coastal communities have only a few possible responses; renourish, armored shorelines, and retreat. Given that coastal tourism is a large economic engine for the state and region, the maintenance of the usable beaches has been the focus of nearly all coastal communities. The placement of sand on eroding beach fronts has been the major response to beach erosion for decades. The magnitude and frequency of renourishment events has strong implications for coastal ecosystems. Here are we focus on the impacts of renourishment at different frequencies on the composition and biomass of benthic infuanal communities.
St. James Internship
Summary coming soon!
Trophic Function Study
Summary coming soon!
Blue Crab Biology and Ecology
Summary coming soon!
Interactive Effects of Nutrient Enhancement and Predation on Estuarine Communities
Summary coming soon!