Local Participation in Nearshore Aquaculture

Just offshore of New Castle, New Hampshire, Sea Grant researchers are teaming up with local fishermen and farmers to create a new model for sustainable, small-scale finfish aquaculture: The AquaFort. 

Funded by the Sea Grant National Aquaculture Initiative’s 2018 aquaculture research awards, the AquaFort was constructed, deployed, and tested by a team at New Hampshire Sea Grant and the University of New Hampshire alongside local fishermen over the past few years. Michael Chambers, Ph.D., is the lead investigator on the project.

It would be something to be really proud of to be able to grow fish and bring them from local waters right to the table. It would be really cool.

— Ward Byrne, FV Sugar Daddy

What is IMTA?

a graphic depicting and describing the function and products of the Aquafort multitrophic aquaculture platform

The Aquafort is an Integrated multi-trophic aquaculture (IMTA) platform,  a self-contained aquaculture system that allows multiple species to grow at the same time within and around a single floating structure. “Multi-trophic” refers to levels of a food web. Each of the different species in the IMTA system provides a benefit to the others.

At the AquaFort, net pens of steelhead trout are surrounded by blue mussels and sugar kelp, which absorb nitrogen waste released by the trout. This nitrogen neutral system has the potential to bring aquaculture to communities around the world looking to grow local seafood and support working waterfronts in an environmentally and economically sustainable way. IMTA methods could be used by fishermen to generate additional income throughout the year and enhance local seafood production to reduce reliance on seafood imports. 

Farmed Species

silvery steelhead trout swimming left to right inside the aquafort

Steelhead Trout

Steelhead Trout

a closeup photo of blue mussels

Blue Mussels

Blue Mussels

sugar kelp, long brown ribbony strips of seaweed

Sugar Kelp

Sugar Kelp

The AquaFort structure is designed for two nets that are 20’ x 20’ x 40’ deep.

aquafort dimensions

The AquaFort structure is designed for two nets that are 20’ x 20’ x 40’ deep.

20-ton (40,000 lb) production capacity per year:

  • 30,000 lbs of fish (steelhead trout)
  • 10,000 lbs of shellfish (blue mussels)

The AquaFort was deployed at the University of New Hampshire (UNH)’s permitted aquaculture research farm, located offshore New Castle, NH. The AquaFort is robustly engineered for nearshore aquaculture and can be scaled to different sizes depending full-time or part-time farming efforts.


Science Communication Specialist
Office: NH Sea Grant, New England Center 214A, 15 Strafford Ave, Durham, NH 03824