Maine seaweed benchmarking: Economically assessing the growth of an emerging sector

Abstract

Seaweed farming in Maine, USA has grown exponentially over the last 5 years. Our work builds upon a prior Maine aquaculture sector benchmarking study to assess changes between the 2017 and 2022 harvest seasons. We interviewed 16 farmers who collectively harvested over 1 million lbs. (wet weight) of seaweed, ∼22 times the harvest volume from the 2017 season. We observed three notable improvements on kelp farms in Maine between 2017 and 2022: (1) median seaweed yield grew by 28%, from 3.3 to 4.24 lbs./ft.; (2) labor efficiency improved by 1,275%, from a median of 7.55 to 103.8 lbs. harvested per hour of labor and management input; and (3) median net margin per pound harvested increased from −$6.41 to $0.16/lb. These gains can likely be attributed to increased farmer knowledge, “learning by doing,” extension support, improved seed production, and increases in scale. When benchmarks were recalculated according to three size groupings, we found that net margins ($/lb.) increased and breakeven price decreased with farm size (total lbs. harvested), indicating economies of scale. We found that fishermen, shellfish farmers, and other members of the working waterfront continue to leverage seaweed farming as a worthwhile source of supplementary income.