AquaFort & IMTA

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three photos in a collage featuring steelhead trout, an aerial view  of an offshore aquaculture raft, and a fisherman with a tote full of trout

Local Participation in Nearshore Aquaculture

New Hampshire Sea Grant’s AquaFort will serve as a nearshore aquaculture training platform and research site. The two-year AquaFort research program will recruit local fishermen and farmers from NH, ME, and MA to participate in workshops and daily operations of an offshore aquaculture farm. During this period (2018-2020) the AquaFort will be constructed and deployed, and two seasonal grow-out trials will be conducted. Participants will benefit from hands-on training in: 

  • Site selection and permitting
  • Cage construction and deployment
  • Fingerling acclimation to seawater and transport
  • Aquaculture of Steelhead trout, mussels, and kelp
  • Farm maintenance
  • Harvest and transport to market
  • Economic analysis of farming the AquaFort
  • Aquaculture business planning

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

Graphic depicting AquaFort dimensions 28 ft by 52 ft

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 will be deployed at the University of New Hampshire (UNH)’s permitted aquaculture research farm is 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.

satellite map of the coast of New Castle, New Hampshire depicting Fort Point an the US Coast Guard station to the left and the AquaFort IMTA site in the middle


Project Objective

Successful execution of the AquaFort program will lead to (1) increased investment and employment opportunities in offshore aquaculture, (2) the production of fresh, local seafood, and (3) reduced reliance on seafood imports.


AquaFort Video

The AquaFort was constructed, deployed, and tested by a team at NH Sea Grant and the University of New Hampshire alongside local fishermen and entrepreneurs. In this video, learn more about the AquaFort and hear perspectives from people involved with the project:


What is IMTA?

Integrated multi-trophic aquaculture (IMTA) is 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