COMMUNITY SCALE SEA VEGETABLE AQUACULTURE: A LOCAL APPROACH TO GLOBAL DIVERSIFICATION OF WORKING WATERFRONTS

Adam T. St-Gelais*, Tollef K. Olson, David W. Fredriksson, Barry A. Costa-Pierce
 
University of New England
Center for Excellence in the Marine Sciences
Ocean Food Systems Group
Biddeford, Maine, USA, 04005
astgelais@une.edu

The economy and character of rural, coastal Maine (USA) has traditionally been closely linked to maritime activities; namely, wild-capture marine fisheries and its allied industries, a trend echoed globally. Economic diversity and by proxy the social-economic sustainability of working waterfronts worldwide has declined as  capture fisheries that support coastal communities have either consolidated or collapsed. Adoption of the sustainable ecological aquaculture of "extractive species" has the potential to augment ocean food system economies, sustain the livelihoods of rural communities, and provide valuable ecosystem services. Aquaculture of marine macrophytes, in our case, sugar kelp (Saccharina latissima) can diversify the revenues while at the same time provide valuable ecosystem services including nutrient remediation (nitrogen and phosphorus), sequestration of carbon, and local amelioration of ocean acidification. When quantified, these ecosystem services can also be leveraged to add value to the prices of ocean food products.

In order for fishermen to successfully transition to farmers a series of key issues must be addressed to lower barriers to entry and increase profitability of sea vegetable farming including 1) Design and engineering of low cost, flexible, ecologically restorative systems, 2) Quantification of ecosystem services, 3) Identification of regionally specific ecological and social carrying capacities for ocean farming, and 4) Market expansion by development of value added products.

Our priority has been to develop low cost, flexible, ecologically restorative farming systems, specifically, we developed and tested a versatile, highly mobile, low cost sea vegetable system for use in protected coastal waters in a suburban area of the Gulf of Maine (GOM) next to our coastal campus. Longline systems currently employed by most seaweed farms are cumbersome and expensive to deploy, relying on 500-1,000kg dead-weight moorings, use rafts and other large, rigid floating structures, and use vertical mooring lines that result in slack and drift of the system during low tides. We developed and successfully tested a system using only locally available materials familiar to the commercial fishing industry in the GOM with up-front costs of less than $600 USD. The system was deployed in November of 2015 and seeded with 2-5mm sugar kelp. Gear performance and production results were monitored throughout. On June 2, 2016, we harvested sugar kelp and the total yield was ~750kg over 50m of seeded line or 14.4 kg/m.