Sea Grant Aquaculture Extension 2010: Enhancement in Marine Finfish and Molluscan Shellfish Aquaculture
The shellfish aquaculture industry spawned over the years in the Great Bay Estuary with very direct N.H. Sea Grant guidance is providing fresh and local seafood to the region and helping area fishermen make a living while also contributing over $1 million in services to the estuarine environment.
RELEVANCE: Over the past few years, a great deal of attention has been focused on the impaired water quality of the Great Bay Estuary, particularly on the need to reduce nutrient inputs. One element of this has been a concern that aquaculture development in the area would exacerbate the problem.
RESPONSE: N.H. Sea Grant has been working for many years to help develop an aquaculture industry in the region, both to assure a supply of quality seafood and to help local commercial fishermen find ways to earn a living while remaining on the water. Various studies have shown that shellfish remove nutrients, including phosphorous, carbon and nitrogen, from their environment 24/7 through their filter feeding. Because of this, NHSG has been particularly interested in developing shellfish aquaculture in the estuary, both in the form of oyster farms and in multi-trophic aquaculture, which combines fish, seaweed and blue mussels.
RESULTS: A NOAA Center for Coastal Monitoring and Assessment study validated NHSG’s approach to the reduction of nutrient loading. The study placed a value of $1.1-1.3 million on the ecosystem services that the current level of shellfish aquaculture is providing the Great Bay Estuary and further estimated that the value could triple with future expansion.
RELEVANCE: In N.H.’s Great Bay Estuary, runoff from impervious surfaces during spring melt and after heavy precipitation generates high nutrient influxes to the bay. Eastern oyster aquaculture has been growing steadily in Great Bay since 2010. It has provided opportunities for commercial fishermen to diversify and the filter feeding oysters have helped reduce the high nutrient levels in the bay.
RESPONSE: The N.H. aquaculture lease process was modified for the bay in 2010. N.H. Fish and Game is now the lead agency with input from N.H. Department of Environmental Services and the Army Corp of Engineers. The new process was aided by researchers at UNH and regional programs, including the Piscataqua Region Estuaries Partnership and the Nature Conservancy. The process now allows shellfish farmers to secure lease sites that can be renewed every five years. N.H. Sea Grant has been instrumental in helping new farmers through the permitting process and with the development of profitable oyster farms.
RESULTS: In 2012, the number of permits jumped from five to eight farms, with over 20 acres in production. This created 10 additional jobs; there are now 22 people working in the Great Bay shellfish industry. The farms are seeded out with more than six million oysters with a farm gate value of over $4 million. This is a 66% increase since 2011 when about four million oysters were in culture.
RECAP: The N.H. oyster aquaculture industry continues to create jobs for coastal N.H., provide a fresh, locally raised product, and help clean up Great Bay.
Multi-trophic Aquaculture Launched in the Piscataqua River
RELEVANCE: The northeast fishing industry has suffered economically due to reduced landings and changing federal regulations, and fishermen are exploring strategies that can sustain their heritage.
RESPONSE: N.H. Sea Grant and UNH have been investigating small-scale, multi-trophic aquaculture in the Piscataqua River. By integrating the production of steelhead trout and mussels on the same platform, fishermen can culture two products for sale while having minimal impact to the ecosystem. Initial permitting was established through N.H. Fish and Game at six sites. However, the EPA stopped the process due to concerns about adding nitrogen to the already nitrogen impaired river. NHSG engaged state and federal agencies, conducted literature searches and calculated nitrogen mass balance models based on the trout/mussel aquaculture concept.
RESULTS: The EPA granted UNH permission to demonstrate the project in 2012. Eight local fishermen were brought on to learn and participate. The project produced 1254 pounds of trout, which sold for $6 a pound at seafood markets in N.H. Ten million wild mussel spat was collected on the cage platform and is now in growout. Expected harvest weight is 7.5 tons by late summer 2013. In the river, nitrogen input from the trout was 103 pounds, while nitrogen absorption and retention from the mussels will be 200 pounds. Therefore the mussels will remove almost twice the nitrogen from the river than the trout added to it. This new culture method will help establish a permitting process for aquaculture in New England, and will also create new sources of sustainable, local seafood, employment and help fishermen diversify into seafood production while still fishing.
RECAP: A new model for integrated multi-trophic aquaculture of steelhead trout and mussels has been accepted by the EPA, one that will benefit both regional fishermen and water quality.
Sea Grant Working with Mystic Aquarium to Explain Aquaculture
NHSG has teamed up with Conn. and Maine Sea Grant to help create aquaculture exhibits at the Mystic Aquarium in Mystic, Conn. The aquarium is constructing a new center for aquarium research and considering exhibits that would highlight locally produced seafood. Working with the aquarium and aquaculture officials from NOAA and the USDA, Sea Grant is helping to provide a positive message about the importance of responsible aquaculture in the U.S.
N.H. and Maine Sea Grant have been collaborating to improve mussel raft technologies. Currently, rafts are constructed from steel, wood and square floats and can produce around 40,000 pounds of mussels per year. The industry wants to expand and move to more exposed sites with higher energies. To do this, rafts will have to be redesigned so that they can survive these sites while increasing the yield per raft. Sea Grant engaged mussel farmers from the two states in collecting data that will be used in the redesign. This information will be forwarded to several high-density polyethylene (HDPE) manufacturers that can create a sea worthy design for offshore culture.
RECAP: The development of oyster aquaculture in the Great Bay Estuary has created jobs, generated income and has reduced nutrients and turbidity in the bay.
N.H. Sea Grant Leading Effort to Combine Steelhead Trout and Mussel Aquaculture in Region
Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant
- New Hampshire raised steelhead trout (2011). Michael Chambers and W. Huntting Howell.
- Marine biofouling, a friend or foe of cage aquaculture (2011). Michael Chambers.