INTEGRATED MULTI-TROPHIC AQUACULTURE OF SUGAR KELP (Saccharina latissimi)  

The University of New Hampshire (UNH) and New Hampshire Sea Grant has recently designed and deployed a floating integrated multi-trophic aquaculture (IMTA) raft for research, outreach and training. This stable, robust platform was designed and demonstrated to culture steelhead trout (Oncorhynchus mykiss), blue mussels (Mytilus edulis) and sugar kelp (Saccharina latissima) simultaneously. State and federal permitting agencies favor this type of aquaculture because the lower trophic, shellfish and seaweed species, extract nutrients from the fish reducing nitrogen input to the ecosystem. The 3D structure, allows farmers to grow multiple species that utilize the 3D water column in a productive manner for greater economic value. Mature kelp from the raft is spawned in captivity and cultured for 6 weeks in a nursery at the UNH Coastal Marine Laboratory. Kelp seed line is then set on the cage mooring lines and vertical lines suspended from the raft in early winter. Harvest initiates in the spring at 2 m length and continues until late July.  Fresh kelp has been sold to restaurants and breweries in Portsmouth, NH for a premium price.