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New Hampshire Department of Environmental Services

Diversifying Shellfish Aquaculture in Coastal New Hampshire

Contract Title: UNH Red Tide Disaster Relief, Diversifying Shellfish Aquaculture
Grantee: University of New Hampshire
Award Period: September 23, 2009-June 30, 2012

Contract Title: Cooperative Agreement with UNH for Little Bay Bathymetric and Substrate Mapping
Grantee: University of New Hampshire
Award Period: May 23, 2012-March 31, 2013

Contract Title: MOA with UNH for Oyster Reef Mapping
Grantee: University of New Hampshire
Award Period: September 19, 2012-March 31, 2013; end-date extended to 5/15/13 following 2/20/13 G & C approval

Original Proposal

This project was designed to prevent future commercial fisheries failures from red tide by making oyster farming more accessible to offshore mussel farmers who are typically more affected by red tide events, and/or others interested in developing or expanding oyster culture operations. The bulk of the project was run by researchers and staff at the University of New Hampshire (UNH). A small component of the project also included provision of technical assistance to prospective aquaculturists, provided by the NH Fish and Game Department (NHF&G) and the NH Department of Health and Human Services. Project end date was June 30, 2012.

Per March 2012 grant amendments, this project was expanded to include efforts to improve GIS data development related to aquaculture planning.

Project Summary

Expanding and Diversifying Aquaculture in NH Waters

The University of New Hampshire (UNH) studied the factors associated with the expansion and diversification of estuarine shellfish aquaculture in New Hampshire. They contended that one potential way to mitigate the effects of a severe red tide season, where blooms mainly occur in coastal or offshore waters, was to develop shellfish aquaculture in estuarine waters. Four objectives were developed to accomplish the project’s goal: characterizing spatial distributions of red tide toxin and other environmental factors potentially affecting molluscan shellfish aquaculture in coastal and estuarine waters, determining the potential (including environmental and social factors) for expanding and diversifying molluscan shellfish aquaculture in coastal and estuarine waters, initiating appropriate efforts to expand and diversify molluscan shellfish aquaculture in estuarine waters, and addressing possible obstacles to expansion of shellfish aquaculture in New Hampshire that were identified in the first three objectives.

UNH produced maps, showing the spatial distributions of environmental and social issues relevant to shellfish aquaculture: red tide toxin data; shellfish harvesting area classifications; location/size of existing aquaculture sites, eelgrass beds, mooring fields and other boating activities; bathymetry; water flow; bottom types; and potential shellfish aquaculture species (eastern oyster, softshell clam, blue mussel, and hard clam).

The overall conclusion, resulting from the mapping efforts and communications with a variety of stakeholders, was that expansion of estuarine shellfish aquaculture in New Hampshire in the near-term will probably occur in the Little Bay area and will likely focus on the eastern oyster (Crassostrea virginica). UNH also recognized the potential for expansion into other geographic areas and involvement of other species.

They considered five major relevant factors in determining the spatial extent of potential shellfish (mainly oyster) aquaculture expansion: red tide toxin distribution, harvest classification areas, water depth, eelgrass distribution, and mooring fields. Considered collectively, these environmental factors indicate that there is a total of approximately 400 acres that are potentially suitable for shellfish aquaculture in Little Bay. Another factor to consider in assessing the overall potential for shellfish aquaculture expansion was distance between farms. The New Hampshire Fish and Game Department (NHF&G) policy requires 50 meters between adjacent farms. Thus, the total acreage available for additional aquaculture sites is also dependent on individual farm size. For planning purposes, polygons representing hypothetical 3-acre rectangular-shaped farm sites with 50m buffers were distributed throughout the potential aquaculture areas, yielding a maximum of 62 farms occupying a total of 186 acres. UNH stated that farm sites of different areas would yield slightly different total coverage possibilities, but a maximum coverage of less than 200 acres of shellfish aquaculture sites for the entire Little Bay area seemed reasonable at the time.

UNH identified four potential obstacles to the expansion of the shellfish industry in NH: the existing state policy of issuing licenses for the duration of only one year, the relationship between state permitting agencies in issuing licenses, public perceptions and opinions regarding shellfish aquaculture, and the relationship of shellfish aquaculture to eelgrass and other factors considered in the permitting process. Two of these obstacles were addressed during the course of this project. A new law came into effect in August 2012 that requires issuance of 5-year licenses, and the relationship between the two major agencies involved in permitting was clarified in 2011 via policy change. Public perceptions and opinions regarding shellfish aquaculture ranged from fully supportive to fully opposed. UNH found that the latter extreme was mainly voiced by those who were opposed to a farm in waters adjacent to their property. Based on comments raised at various public meetings as well as other venues where shellfish aquaculture was discussed, it seemed clear that better communication of what is involved in shellfish farming—including the range of environmental and economic benefits as well as potential negative impacts—would help facilitate the expansion process.

UNH developed a booklet to provide prospective shellfish aquaculturists with the information relevant to the permitting process. The booklet describes the overall process for obtaining a Marine Aquaculture License and provides relevant contacts, an example of a best management practices (BMP) plan, information concerning the various permits typically required for operating a farm, and other useful information. The booklet also aims to supplement information routinely provided by NHF&G, the major permitting agency for shellfish aquaculture, to prospective shellfish farmers. This booklet is included as Appendix D of the project’s final report. UNH also provided a technical permitting workshop for potential aquaculturists at the 2011 Northeast Shellfish Sanitation Association (NESSA) meeting, which was hosted by NHDES.

UNH stated that shellfish aquaculture is rapidly expanding in New Hampshire. By the end of the project (July 2012), four new licenses for oyster farms had been issued. They stated that there is widespread support for further development of shellfish farming in the state, but there are constraints as well as focused resistance. The major social issues that need further attention include: how shellfish aquaculture is viewed by residents who are abutters to the farms, the relationship of shellfish aquaculture to water quality management at state and federal levels, and the relationship of shellfish aquaculture to local and state planning efforts. UNH concluded that the shellfish industry’s success and expansion will depend on how well it becomes integrated into the overall, evolving management process.

NHDES developed GIS data and maps in order to effectively provide support to aquaculture planning. These files included documenting the location and size of historical and existing aquaculture sites, mapping the location of moorings and mooring fields within estuarine waters, and standardizing the shellfish harvesting area classification boundaries. These developed and expanded data will further inform the planning and evaluation of potential future aquaculture sites.

Little Bay Bathymetry

NHDES partnered with the University of New Hampshire Center for Coastal and Ocean Mapping (CCOM) to develop a complete bathymetric dataset for Little Bay. Many existing datasets for Little Bay lacked information for shallow water environments, which was a real impediment to shellfish aquaculture planning and evaluation. CCOM had the technology to complete detailed surveys of shallow water environments using methods consistent with those already used for a 2009 bathymetric assessment of Great Bay. The original proposal planned for CCOM to prepare bathymetric surveys of the tidal waters in Little Bay and to implement and evaluate new technologies to concurrently map substrate type with bathymetry.

A bathymetric survey of Little Bay Estuary was conducted on 16 days in the months of February and March 2013 using a dual-frequency (24 and 200 khz) single-beam sonar system. Survey data were collected onboard the R/V Galen J, a 22 ft open-cabin vessel with 75 hp outboard motor. The survey extended from the General Sullivan Bridge in Newington, NH to Adam’s Point in Durham, NH and spanned the width of the estuary to within 20-50 m of the high tide shoreline.

As a result of this bathymetric survey, UNH CCOM developed a complete bathymetric dataset for Little Bay. Additionally, CCOM used their technology to collect "backscatter" data from the echo-sounder, which may prove useful in characterizing bottom substrate. Characterizing bottom substrate with backscatter data was not part of this contract, but the raw data have been processed and archived and will be used in future research projects. The new bathymetry data have been processed by CCOM and referenced to the mean lower low water mark. Geographic Information System (GIS) specialists in NHDES manipulated the point-data from CCOM to create GIS shapefiles with bathymetric contours in Little Bay. The same was done with Great Bay bathymetry previously created by CCOM in 2009 with other funding sources. These datasets will be very useful for future aquaculture site planning and evaluation. It should be noted that the bathymetry data are not intended to be used for navigational purposes.

Piscataqua River and other tributary bathymetry

The March 2012 grant amendments included plans to support bathymetry mapping in the Piscataqua River and other tributaries. The purpose of the project was to develop recent, comprehensive bathymetric surveys of the Piscataqua River and other tributaries because they were areas where aquaculture might be permitted in the future. In this effort, the University of New Hampshire Center for Coastal and Ocean Mapping (CCOM) was to develop new data using the same methods employed for the Little Bay bathymetry work. After assessing progress on the Little Bay bathymetry work and discussing the logistics with CCOM, a decision was made in January 2013 to limit bathymetric mapping to Little Bay and not pursue mapping in other areas.

Existing Shellfish Resource Mapping

NHDES acknowledged the need for more recent, comprehensive information on existing wild shellfish resources in order to properly plan for future aquaculture activities. A contract with the University of New Hampshire (UNH) to conduct oyster reef mapping on six reefs was approved in September 2012 and was amended in February 2013 for mapping of up to eight additional sites. The primary objectives associated with this project were to determine the spatial extent of six major natural oyster reefs in New Hampshire, to map the extent of live oyster bottom at selected recent oyster restoration sites, and to map areas where oyster beds had been known to occur historically. UNH used towed underwater videography at 12 oyster reefs in the Great Bay Estuary during October 2012, November 2012, and June 2013. All imagery was reviewed in the laboratory and classified into one of three categories: "reef: (>20% shell cover and live oysters visible); "sparse shell: (<20% shell cover); and "non-reef: (no shell or live oysters).

UNH mapped six major natural oyster reefs in the Great Bay Estuary (Adams Point, Nannie Island, Oyster River, Piscataqua River, Squamscott River, and Woodman Point) to determine the areal coverage of "shell bottom.: These reefs had been surveyed several times since 1997 by the New Hampshire Fish and Game Department (NHF&G) and UNH, and the aim of the 2012 mapping was to provide data that could as directly as possible be compared to previous surveys. Because of differences in methods used for the different studies, including what qualified as "shell bottom,: it was not possible to accurately infer changes in bottom area over time. However, some reasonable conclusions could be drawn on an individual reef basis, and those conclusions were presented in the final report.

Selected oyster restoration sites were video surveyed in 2013 to determine bottom area coverage that could be considered "reef: and therefore considered as part of the overall oyster resource in New Hampshire. Restoration sites in the Lamprey River, Oyster River (3 sites), and Fox Point were imaged. Due to poor image quality, full bottom area coverage could not be determined for any of the sites. Nonetheless, substantial areas of at least "sparse shell: bottom and some areas of live oysters were recorded at all sites. These restoration sites as well as additional sites are scheduled for video surveying and quantitative sampling in 2013 through other funding sources.

UNH mapped areas where oyster beds were historically thought to exist but had not been surveyed in recent years. Of the four general areas surveyed, live oyster reefs were found in two areas: Lamprey River (0.9 ac) and mid-Great Bay (35.2 ac). These two areas represent a major addition to the known live oyster bottom in the state, and the findings strongly suggest that live oyster reefs may be in other areas where oysters have not been known to exist in recent years.

The project also mapped several areas in Great Bay that do not have dense living oysters, but do have shell substrate near live reefs and therefore may be suitable candidate sites for future restoration efforts. UNH estimated that >100 acres of bottom area in Great Bay likely represents excellent oyster restoration opportunities. These are exciting discoveries because the region has an active oyster restoration program run through The Nature Conservancy, and the location of these potential restoration sites has been relayed to this organization so they can consider them in future restoration efforts.

Overall, this project substantially added to the knowledge of live oyster reef locations in New Hampshire as well as the total bottom area coverage. A total of 120 acres of bottom area classified as "reef: were mapped, and >100 acres of bottom area that presents excellent oyster restoration opportunities have been identified.

NHDES also developed shellfish resource data in-house with staff supported under the grant. Although NHDES staff had developed a Geographic Information System (GIS) layer that included historical information on the spatial extent of shellfish resources, it was determined that NHDES needed to continue data development, focusing on areas that were not yet included in the existing GIS data layer or in areas that had generalized or outdated information. A NHDES seasonal intern was hired in March 2013 to assist with this field work and the computer processing of the data. The focus of the NHDES intern work was to identify and map blue mussel resources in coastal NH, as the occurrence of this species had not been well-represented in the current GIS data.

At the start of the project, there were 12 blue mussel beds represented in GIS data. NHDES staff visited those 12 mussel beds, as well as areas suggested by the New Hampshire Fish and Game Department and areas that had the appropriate characteristics for blue mussel habitat. By June 2013, there were 24 blue mussel beds mapped and represented in the state GIS file that spanned the entire NH coastline. Five of the original blue mussel bed delineations were deemed accurate after a site inspection, and 19 new blue mussel beds were mapped. The project also included the development of a field methodology to assess mussel bed density. This method could only be applied to one site during the project due to field conditions and other constraints, but it will assist NHDES staff in future mapping initiatives.

Reports and Products



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