Kappaphycus alvarezii

Ganesan, Review Meenakshisundaram, Trivedi, Nitin, Gupta, Vishal, Madhav, S. Venu, Reddy, Chennur Radhakrishna & Levine, Ira A., 2019, Seaweed resources in India - current status of diversity and cultivation: prospects and challenges, Botanica Marina (Warsaw, Poland) 62 (5), pp. 463-482 : 469-470

Kappaphycus alvarezii

Kappaphycus alvarezii is one of the most widely traded tropical red seaweeds, utilized as a source for the extraction of the commercially important phycocolloid kappa-carrageenan (κ- carrageenan). Due to its unique gelling properties, kappa-carrageenan is used as an emulsifier, binder, thickener and gelling agent in a diverse range of products including toothpaste, cosmetics, ice cream, pet foods, beverages, pharmaceuticals, personal care and dairy products.

Farming of Kappaphycus alvarezii in India originated with a few grams of biomass imported from Japan by CSIR-CSMCRI in the early 1990s; the importation followed the quarantine procedures appropriate for cultivation and utilization. Initial out-planting trials were done along the Northwest’s Okha coast following laboratory acclimatization studies. Subsequently, southeast Tamil Nadu’s Mandapam coast was explored for its suitability as a potential cultivation region from 1995 to 1997. Initial field trials evaluated a variety of cultivation methods, including (a) polythene bags, (b) fish net bags and (c) net enclosed open culture ( Eswaran et al. 2002). Eventually, the bamboo raft method was adopted. In this method, 3 × 3 m rafts made with 7–8 cm diameter bamboo were reinforced utilizing diagonally orientated bamboo braces approximately 1.3 m long to maintain integrity in open sea conditions. Lower portions of the rafts were covered with fishing net minimizing grazing and biomass drifting. Twenty plantings (fresh cuttings) of approximately 100 g. each were attached to raft ropes (3 mm thick polypropylene) at regular intervals using a braider. The seeded ropes were tied at both ends of the bamboo rafts at 15-cm intervals. Initial seeding weight of each raft averaged 40 kg fresh wt. and rafts were moored in clusters of 5–10 and anchored to 30-kg mooring stones. Deployed seaweed cuttings began growing immediately and were harvested after a growth period of approximately 45 days ( Figure 8A,B ; Mantri et al. 2017).

Kappaphycus alvarezii commercial cultivation was initiated in 2001 along the southeast coast of Tamil Nadu by Pepsico India Holdings ( P) Ltd., Gurgaon, India after licensing cultivation technology from CSIR-CSMCRI, Bhavnagar. The company successfully adopted a contractfarming model with buy-back arrangements for seaweed produced by the women’s Self-help Groups (SHGs). Infrastructure was provided to the SHGs through the national bank subsidies. The contract farming model allocated 45 rafts to each SHG individual member. The amount of distributed rafts was tied to the planting and harvesting 45-day scheduled farming period. Each farmer could conveniently plant and harvest one raft per day. Harvests averaged 240 kg of live seaweed per raft with approximately 40 kg used as raft seeding material for the subsequent farming cycle, leaving 200 kg of fresh biomass or 20 kg of dry seaweed available for sale. More than 1500 households along the Tamil Nadu coast engaged in seaweed farming as an alternative livelihood, each earning approximately US $300 per month ( Table 1) .

Seaweed cultivation has emerged as viable option for the economic improvement of low income coastal communities in India ( Krishnan and Narayanakumar 2010, Periyasami et al. 2014, 2015, Mantri et al. 2017). Production increased significantly from 21 dry metric tonnes in 2001–1490 dry tonnes in 2013, totaling 7187 dry tonnes biomass, worth US $2.5 million during the 13-year cultivation period ( Mantri et al. 2017). Kappaphycus alvarezii commercial farming from Tamil Nadu experienced a

Tamil Nadu and expansion is underway in Gujarat, where commercial activities commenced in 2017.

Hypnea musciformis

Hypnea musciformis (Wulfen) J.V. Lamouroux is an indigenous carrageenophyte yielding kappa-carrageenan. Hypnea musciformis is found in natural beds along the shorelines of several Gulf of Mannar islands. Lagoon waters of Krusadai Island were selected for pilot-scale cultivation of H. musciformis utilizing the monoline method ( Figure 9 ; Ganesan et al. 2006). Young actively growing apical portions of H. musciformis ranging from 2 to 2.5 g fresh wt. and 5 cm long, were inserted between the braids of 20-m long coir ropes made from coconut husks. The ropes were anchored to wooden stakes and kept afloat with plastic floats. A total of 2000 m of coir ropes were seeded and placed in 10 plots, each consisting of 10 ropes, each 20 m long. Hypnea was harvested at 25-day intervals reaching 30–35 cm lengths. Thalli were clipped leaving fragments to grow further. Harvests ranged from 250 to 300 g fresh wt m−1 rope ( Ganesan et al. 2006). Fifteen harvests per year yielded a total biomass of 38–40 tonnes fresh wt ha−1 year−1 ( Ganesan et al. 2006).

significant decline in 2013 correlated with a sudden rise in seawater temperature to 36°C and a subsequent onset of bacterial disease. Crop production yields slowly recovered starting in 2016 and increased production is anticipated in the next couple of years. Kappaphycus alvarezii commercial production has expanded to six coastal districts in

Figures

Figure 8: Kappaphycus alvarezii cultivation. (A) Raft seeded with K. alvarzii; (B) K. alvarezii grown on raft.

Figure 9: Monoline method of cultivating Hypnea musciformis. (A) Well grown H. musciformis on coir rope; (B) a pilot scale farm of H. musciformis with 2000-m long coir rope.