New Approaches to Seaweed Aquaculture: Developing a Biosecure and Reliable Seed Stock for the Emergent Northeast Edible Seaweed Industry

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Commodities

• Vegetables: other

Practices

• Crop Production: crop improvement and selection, seed saving

Seaweed farming is the second largest aquaculture industry worldwide, with global production used in cuisine, manufactured foods, fertilizer, and animal feed. Sea vegetables (the edible subset) are a $6 billion market worldwide and a growing industry, particularly in the Northeast US where commercial species are native. In the Northeast there are >200 established seaweed farms currently in operation as well as ~6 seaweed nurseries that supply these farms. Techniques for growing sea vegetables (both brown and red algae) are well established despite a complex two-part life cycle, but the US industry has been slow to adopt the more technically advanced germ line cultivation techniques used in Asia and Northern Europe. Instead, US farmers rely upon provision of tenuous wild-sourced seed to cultivate juvenile sporophytes for product, an outdated approach subject to natural vagaries in environmental conditions and stochastic changes in reproductive timing, fecundity, and seed quality. To increase production for novel emerging US seaweed markets, an investment into the technological methods for mechanization of seed stock development and preservation are needed. Annually, sea vegetable nurseries require access to sterilized seawater and sufficient lighting, space for care and maintenance of seed stocks, and expertise, making seedling cultivation a barrier to entry for most new aquaculturists. With the development of seed or broodstock cryopreservation, this provides ‘insurance’ for common and specialized strains, minimizing manual labor associated with long-term cultivation and shortened turnaround times for the production of healthy, viable, juvenile sporophytes on ‘seeded-lines’ that can be sold to farmers.

The proposed study seeks to develop long-term maintenance technologies for current (Sugar kelp - Saccharina latissima) and emerging seaweeds (Winged kelp – Alaria esculenta, Irish moss – Chondrus crispus, and Dulse – Palmaria palmata) in the Northeast by testing the efficacy of various sterile cryopreservation techniques for storage of vegetative cultures and spores.

Laboratory experiments will be used to develop cryopreservation approaches and will be initiated by harvesting wild broodstock (spores) of commercially emergent seaweeds and subjecting these spores to different freezing and thawing rates and cryoprotectants. Initial results for sugar kelp (Saccharina latissima) spores indicate that controlled-rate-freezing (CRF) is more effective than flash freezing.  Using live-cultured spores, the traditional culturing technique will serve as a control and will be compared to revival culturing using preserved/thawed seed stocks. Accurate indication of viability is critical to developing quality control measures for nurseries seeking to offer cryopreservation services. We plan to engage both a hatchery/nursery (Atlantic Sea Farms) and a seaweed farm (Maine Sea Farms) to test the feasibility and ease of implementation of cryogenic protocols as well as provide seeded lines for grow-out tests of both brown and red algae for on-farm trials.

Edible seaweeds are a $6 billion USD market worldwide. Globally, the seaweed aquaculture sector is growing 7.7% annually, and a rate twice that in the Northeast US where many commercial species are native. To increase production for novel emerging US seaweed markets, an investment into the technological methods for mechanization of seed stock development and seed preservation are required. We propose to develop and optimize a well-established method for cryopreserving (freezing), thawing and growing juvenile seaweed vegetable species in biosecure nurseries. The method maintains frozen cultures of the microscopic life stage (spores) of current farmed seaweed vegetables and emerging species.