MORPHOLOGICAL VARIABILITIES OF Saccharina latissima FARMED IN EXPOSED VS PROTECTED SITES IN SACO BAY, MAINE

In order to proactively  asses an industry with serious economic and environmental potential the US Department of Energy (DOE0) ARPA-e program has funded research for future seaweed farming in the United States through the MacroAlgae Research Inspiring Novel Energy Resources (MARINER) program. Through this program a team lead at the University of New England (UNE) is conducting model based design validation via in-situ wave, current and resulting farm forces at two Sugar kelp (Saccharina latissima ) farm sites in Saco Bay, Maine; one protected and one exposed.

As is typical of current siting practices for most kelp farms in the nearshore Gulf of Maine, the protected site (a 60m (200ft) single long-line kelp farm) is sited in a protected environment located in lee of an Island to decrease potential  physical and biological challenges created from strong waves, currents and harsh winter storms.  This approach however will limit growth of the industry and moving offshore will allow farmers to achieve greater scale with fewer stakeholder conflicts.  MARINER aims to  yield designs for large-scale, offshore seaweed farming in open ocean conditions .

Understanding site-specific morphological, geometric and material property differences of kelp grown in both  protected and exposed sites in Saco Bay, ME will aid accurate, model driven farm design performance. Here farm and blade scale growth, morphology and material property data were collected across protected and exposed farm sites during winter 2018-2019 to assess differences between sites .  Between March and May of 2019, twelve successful sampling events provided data that indicates variations in peak biomass, across the entire farm, between protected and exposed sites with the protected site showing earlier peak growth by half a week compared to the exposed site. At this growth peak blade length, stipe length and overall length of the sporophytes sampled were between 220mm-276mm longer than the sporophytes sampled from the exposed site, in each length category. A month later, the exposed site grew beyond the protected site between 817mm-851mm in total and blade length and by 34mm in stipe length. A developed understanding of morphological variabilities between protected and exposed sites could influence future modeling, farm  design, and biomass and harvest projections.