Gelidiella acerosa

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 : 471

Gelidiella acerosa

Gelidiella acerosa is the preferred source of raw material for the production of Indian pharmaceutical and bacteriological grade agar with a gel strength ranging from 850 to 2200 g cm 2 ( Ganesan et al. 2015b). Indian agar processors produce an average of 100 tonnes of pharmacological grade agar from G. acerosa . Unscrupulous harvesting of natural seaweed beds continuously led to gradual reduction of wild standing stocks. The over exploitation of natural Gelidiella populations necessitated the development of cultivation methods for farming seaweeds. Initial methods included long-line ropes ( Subbaramaiah et al. 1975), single rope floating technique (SRFT; Subbaramaiah and Banumathi 1992), coral stone culture method ( Patel et al. 1986), and concrete stone method ( Ganesan et al. 2009). These methods resulted in low biomass yields and were difficult to manage in terms of planting, monitoring and harvest practices. Therefore, it became necessary to develop improved methods resulting in higher biomass and easier cultivation operations. The bamboo raft method successfully used for the commercial cultivation of Kappaphycus alvarezii was adopted for G. acerosa ( Figure 11A ; Ganesan et al. 2009) yielding significantly higher harvested biomass than previous methods. The suspended stone method was developed to enhance the bamboo raft method by tying approximately 2 g of seedlings to nylon thread, which was wound around the stones (15–70 cm 2 area and 100–200 g weight) and hung 5 cm below the polypropylene ropes (3 mm diam). The polypropylene ropes were tied across the bamboo frames of 1.5 × 1.5 m size. The suspended ropes orientated the algal thalli upwards. Eight inoculated stones were tied to each rope with 10 polypropylene ropes per square raft (2.0 × 2.0 m). Each raft was seeded with 160 g fresh biomass equivalent to 71 g fresh wt m−2. Harvesting entailed cutting erect thalli and leaving the basal portions on the stones for further growth ( Figure 11B ). The stone-modified raft method resulted in three harvests per year yielding 8–15 kg fresh wt raft−1 per harvest ( Ganesan et al. 2011).

Figures

Figure 11: Gelidiella acerosa cultivation. (A) Raft method; (B) suspended stone method.