Gracilaria dura

Gracilaria dura

Gracilaria dura (C. Agardh) J. Agardh attracts significant interest as a source of agarose with a gel strength of 2200 g cm−2, gelling temperature of 30°C and sulfate content of 0.15% ( Prasad et al. 2007). The distribution of G. dura is restricted to the west coast of India. Several experimental scale cultivation methods were initiated along India’s southeast coast including the bottom net, net bag, net pouch and bamboo raft methods ( Veeragurunathan et al. 2015). Ultimately, the bamboo raft method resulted in the largest yield. Bamboo rafts (2 × 2 m size), with initial plant density of 1.2 kg fresh wt raft−1, yielded 8 kg fresh wt raft− 1 in 45- to 60-day cultivation cycles. Six harvests were achieved in a year ( Figure 13A View Figure 13 ).

Recently, an initial cultivation effort for G. dura along the Simar, Gujarat coast, in northwest of India has utilized the tube-net method. The tube-net method’s seed material (10 kg fresh) was uniformly loaded in 25-m tube nets made from fishing nets and sealed at both ends with polypropylene rope ( Figure 13B View Figure 13 ), then transplanted in rows to the shallow coastal waters with anchor supports and floats. The daily average growth of G. dura ranged from 2 to 3% day−1 and the yield was 30–35 kg fresh biomass in 40–45 days (Mantri, personal communication).