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In an effort to develop suitable culture techniques for macroalgae in the Northeast, this guide reviews the current knowledge of Sargassum biology and reports on culture techniques learned during a research exchange between the United States (NOAA Sea Grant) and South Korea (National Fisheries Research and Development Institute). The authors would like to acknowledge Drs. Miseon Park, Young Dae Kim, and Eun Kyung Hwang from the National Fisheries Research and Development Institute.  Supported by Sea Grant and NOAA-MOF Joint Project Agreement on Integrated Multi-Trophic Aquaculture, through the Joint Coordination Panel for Aquaculture Cooperation for US-Korea. Sargassum (Family Sargassaceae, Order Fucales) represents the most  common species of brown macroalgae in tropical to warm temperate waters (Guiry and Guiry 2013). It is the most diverse genus of marine macrophytes with more than 130 described species (Xie et al. 2013), with 28 species in Korea (Hwang et al. 2006). Sargassum species, collectively referred to in this document as sargassum, include a wide variety of forms and reproductive strategies (Mattio and Payri 2011) that provide important ecological and economical benefits including nutrient cycling  (Wanders 1976, Carpenter and Cox 1974). Intertidal and subtidal sargassum beds provide food, habitat, and nursery grounds for a wide array of marine organisms (Tsukidate 1992), while also providing food, alginates, feed, and bioactive compounds for people who harvest or culture sargassum (Belleme and Belleme 2007, Zhao et  al. 2008, Xie et al. 2013)(1)

Sea cucumbers are a valuable fishery around the globe. The United Nations Food and Agriculture Organization (FAO) estimated the global production from both aquaculture and capture fisheries to be 153,183 metric tonnes in 2011 (FAO 2013a). Of that production, roughly 85% is the Japanese sea cucumber Apostichopus japonicus (1). Sea cucumbers are developed into a variety of products including dried muscle, fermented guts, and dried gonads (FAO 2013b). Wild stocks have been heavily fished in many areas around the world. As a result of overfishing, sea cucumber culture techniques have been developed for variety of species. Hatchery production has centered in the Pacific Rim and is used both as a source of juveniles for various culture activities and for stock enhancement and restoration efforts. Currently hatchery production exists for approximately a dozen different tropical and temperate species (Purcell et al. 2012, Table 1).

Integrated Multi-trophic Aquaculture (IMTA) efforts in northeastern North America have focused on various combinations of fish, shellfish, and algae. Sea cucumbers have been proposed as one potential species that could be added as a consumer of benthic deposits. Within the Gulf of Maine, the predominate sea cucumber species, Cucumaria frondosa (2), has been fished commercially in Maine since 1990. Landings peaked in 2004 with a harvest of just over 10 million pounds (ME DMR 2013). The value of the fishery in Maine fluctuated between $66,000 and $562,000 from 1994 until the peak in 2004. The price per pound has more than tripled since the peak harvest in 2004. The economic value for the Maine fishery is based on the boat price paid to fishermen, and does not represent the significant increase in value that occurs with processing into various final consumer products.

Sea cucumbers from the Maine fishery traditionally have gone to the Asian food market, however the potential for various nutraceuticals may represent a higher value use. For example, trials are underway to examine the potential for Frondoside A, a compound extracted from C. frondosa, to treat cancer (Attoub et al. 2013). At least one company in the region is processing sea cucumbers for the extraction of various nutraceuticals.

A recent review of the potential for culture of C. frondosa in the Northeast (Nelson et al. 2012a) highlighted advantages and challenges for commercial culture of this species, in particular under IMTA. Strengths include an existing market for the product with good potential for increased nutraceutical use, a well-understood reproductive biology (especially for populations in the St. Laurence River area), and evidence that C. frondosa would be a suitable species for integration in IMTA farms as a benthic filter feeder. Culture of this species faces several challenges. These include a relatively low market price, even when the fishery was at its peak, due to the thinner muscle wall, a long grow-out period, and a lack of published techniques for culturing this species.

Thallus consisting of root-like holdfast, short stipe and blade. Blade long-belt shaped, up toone meter long, 10-20 cm broad, with margin undulate and overlapping, thick at the middleand thin at the margin. A short and small stipe and holdfast at the base of the blade. Holdfaststurdy (presenting haptera) with which the algae is fixed to rocky substratum.Colour: thickdark green; blade surface brown, occasionally glaucescent.

Thallus erect or prostrate (decumbent), branched subdichotomously, laterally, secondly, radially or irregularly; axes and branches terete to flattened. Attached to solid substratum by a small discoid holdfast or living on sandy bottoms with part of the thallus immersed in the sand. Sometimes loose lying or floating in calm waters. Uniaxial construction but appearing multiaxial, pseudoparenchymatous with a small celled medulla.
Life history triphasic with isomorphic gametophytes and tetrasporapytes. In the genus Gracilaria, cystocarps exhibit traversing nutritive cells between the carposporophyte and the pericarp and spermataagia are in pits or conceptacles. In the genus Gracilariopsis, cystocarps lack the traversing nutritive cells and spermatangia are superficial.