World Aquaculture - December 2023

WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2023 67 powered modules at the surface can power tip thrusters on the rotor for increased upwelling during summer when upwelling might be most needed. Several iterations of the upweller device have been evaluated on the west coast of North America (Fig. 7). Recently, the DOE ARPA-E Mariner program provided Otherlab with additional funding to continue their R&D with the ROV and the Upweller for another year. Results from the Farm In the spring of 2022, the farm was harvested, and all structures were removed from the site. Kelp was harvested from the composite rod at a yield of 8 kg/m. No interactions with marine mammals were observed during the deployment. Analysis of the composite rod after deployment is ongoing. The composite kelp farm survived winter storms with waves up to 6 m in height. Due to the positive performance of the novel mooring system, we are investigating additional applications. For example, we believe larger diameter composite rod (2.5 cm) could be used to moor a fish cage. Conclusion A novel structure for cultivating macroalgae at exposed ocean sites was successfully designed, deployed, and tested. The findings indicated that using composite rods as mooring and structural members of aquaculture farms warrants further investigation. Future work on this technology should include streamlining operations and quantifying longevity of fiberglass mooring components. Future research will be explored at UNH with custom fabricated composite rods that break cleanly with a bending radius less than that of an adult north Atlantic right whale fluke or tail. A fourth iteration of the ROV anchor installer is now operating somewhat routinely. It has operated at depths of up to 30 m and has installed multiple anchors with pullout tests exceeding five metric tons. A 7.5 m diameter upweller has been evaluated in Monterey Bay with demonstrated wave-powered operation. A flow rate averaging around 5m3/s was also demonstrated under battery power. The development of the ROV anchor installer and upweller are ongoing. Acknowledgments A special thanks to co-authors M. R. Swift, Igor Tsukrov, Michael MacNicoll, Mellissa Landon and Jon Pompa for their hard work and dedication to the project. Notes Michael Chambers*, M. Robinson Swift, Igor Tsukrov, School of Marine Science and Ocean Engineering, University of New Hampshire, NH, USA. Zach Moscicki, Tobias Dewhurst, Michael MacNicoll, Kelson Marine, Portland, ME, USA. Peter Lynn, Jon Pompa, Otherlab, San Francisco, CA, USA. Beth Zotter, Umaro Foods, Berkeley, CA, USA. Melissa Landon, Stationkeep LLC, Portland, ME, USA. * Corresponding author: Michael. References Browning, T.J. and C.M. Moore. 2023. Global analysis of ocean phytoplankton nutrient limitation reveals high prevalence of co-limitation. Nature Communications 14: Article number 5014. articles/s41467-023-407740#:~:text=Here%20we%20 synthesize%20available%20 experimental,in%20regions%20 in%20between%20the Moscicki, Z., M.R. Swift, T. Dewhurst, M. MacNicoll, M.D. Chambers, I. Tsukrov, D. Fredriksson, P. Lynn, M. Landon and B. Zotter. 2023. Design, deployment, and operation of an experimental offshore kelp cultivation structure. In review in Aquaculture Engineering. Moscicki, Z., M.R. Swift, M. MacNicoll, D. Fredriksson, I. Tsukrov and M.D. Chambers 2023. Evaluation of an experimental kelp farm’s structural behavior using regression modelling and response amplitude operators derived from insitu measurements. In review in Aquaculture Engineering. Moscicki, Z., T. Dewhurst, M. MacNicoll, P. Lynn, C. Sullivan, M.D. Chambers, I. Tsukrov, M.R. Swift and B. Zotter. 2022. Using finite element analysis for the design of a modular offshore macroalgae farm. The 9th Conference on Computational Methods in Marine Engineering (Marine 2021) 1 (1): 1–11. Yao, Z., W. Fan, C. Xiao, T. Lin, Y. Zang, Y Zhang, J. Lio, Z. Zhang, Y. Pan and Y. Chen. 2020. Numerical studies on the suitable position of artificial upwelling in a semi-enclosed bay. Water 2020, 12(1), 177. FIGURE 7. Upweller in development that utilizes solar and wave energy to spin and push nutrient rich, deep water toward the surface to fertilize kelp. FIGURE 6. Robotic ROV that spins helical anchors into the bottom to moor the kelp farm.