World Aquaculture - December 2023

WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2023 65 The University of New Hampshire, working together with Umaro Foods, Otherlab, Kelson Marine and Stationkeep LLC, developed a composite (fiberglass), subsurface array for cultivating macroalgae in the open ocean. The project was part of a larger national effort funded by the US Department of Energy ARPA-E’s MARINER program to develop technologies that enable largescale macroalgae cultivation for the purpose of generating material for sustainable human food, animal feed and biofuel. This project investigated 1) kelp culture materials that could reduce marine mammal entanglement, 2) a remotely operated vehicle (ROV) that spins helical anchors into the seafloor to moor the farm and reduce costs, and 3) an upweller device to bring deep, cold, nutrient rich water to the surface to enhance kelp survival and growth (Fig. 1). Offshore aquaculture structures deployed in the Gulf of Maine are perceived to pose potential risk to the endangered North Atlantic Right Whale through entanglement, thereby making permits for such systems difficult to obtain. To overcome this challenge, the project designed, modeled, and deployed a farm for the cultivation of sugar kelp (Saccharina latissima) that featured marine animal entanglement mitigation measures including replacement of synthetic fiber ropes with composite fiberglass rods. The composite rod has a high tensile strength, resists bending, and breaks at a predictable bending curvature. This reduces the chance of the rod wrapping around a whale appendage before it breaks. Like a piece of uncooked spaghetti, a composite rod will snap rather than be bent into a loop. We believe that the chances of marine mammal entanglement can be reduced by replacing synthetic fiber ropes with composite rods (Fig. 2). The project deployed an experimental farm in the fall of 2021 at an exposed site near Camp Ellis, ME. The permitted site was operated by the University of New England, whose staff assisted in operations at the farm. The project demonstrated the composite line technology in the context of a multi-module kelp cultivation array deployed at an exposed site during harsh winter conditions characteristic of the Gulf of Maine (Moscicki et al. 2023). Composite Kelp Farm (AquaFields) The novel farming system (Fig. 3) was designed with limited use of rope, which is perceived to pose an entanglement risk to marine animals, particularly when slack. Instead, the mooring and kelp substrate components were comprised of tensioned semi-rigid fiberglass rods that resist bending. We hypothesized that this would allow better shedding of the gear during a potential interaction event with marine mammals. However, quantifying what would occur in such an event A New Paradigm in Offshore Macroalgae Farming: Reducing the Risk of Marine Mammal Entanglement Michael Chambers, Zach Moscicki, Peter Lynn, Tobias Dewhurst and Beth Zotter (CONTINUED ON PAGE 66) FIGURE 2. Illustration of a whale encountering a fiberglass rod and bending it until it breaks. FIGURE 3. Diagram showing the components of an open ocean macroalgae farm using a novel mooring system and wave powered upwellers developed through the ARPA-E funded project. FIGURE 1. Conceptual diagram of an offshore kelp farm with wave and solar powered upwellers to provide deep, nutrient rich water to the kelp.