Mariculture of Hypnea musciformis (Wulfen) Lamouroux in South east coast of India

Abstract

Exploitation of agar, algin and carrageenophytic seaweeds in south east coast of India has increased significantly over the past few decades. Hypnea musciformis is one of the species exploited and the harvesting pressure could have negative consequences on the sustainability of this resource. Although demand for raw material of H. musciformis continues to increase, basic knowledge on requirements to cultivate this indigenous carrageenophyte is lacking. In this study, experiments were conducted along the south-east coast of India for 21 months from June 2001 to February 2003 on the seasonality of growth of H. musciformis, growth on polypropylene and coir ropes, the effect of seedling density, depth of water and duration of culture period to optimise its field cultivation. Biomass yield (g fw m − 1 ) and Daily Growth Rate (DGR) (%) were determined. Results showed that the biomass yield was lowest in January (8.0 ± 1.5 g fw m − 1 ) and significantly different ( P < 0.001) than the highest biomass yield in August (403.0 ± 10.0 g fw m − 1 ). Biomass yield increased with increase in seedling density (30 g fw m − 1 and above). Higher DGR (7.6–10.9%) were determined for 10 g fw m − 1 initial seedling density and it differed significantly ( P < 0.001) from the DGR of all other seedling densities. The depth of water had a considerable effect; biomass yield (130.0 ± 15.0 g fw m − 1 ) and DGR (7.0 ± 0.6%) were maximum at the surface (0 cm depth) and significantly different ( P < 0.001) at depths of 30, 60, 90 and 120 cm. Duration of cultivation period was not a limiting factor in H. musciformis. The higher biomass yield was obtained in 75 and 150 days after plantation. Biomass yield (35.0 ± 4.5 g fw m − 1 ) and growth rate (3.8 ± 0.2%) were lowest in minimum duration (25 days) and significantly different to 150 days after plantation ( P < 0.001) during all culture periods. Biomass yield (50.0–305.0 g fw m − 1 ) and DGR (3.8–9.6%) were consistently higher on coir rope and significantly different ( P < 0.001) when compared to polypropylene rope during all culture months. The observed seasonality of response to culture H. musciformis; higher biomass yield in higher seedling densities; higher biomass yield and DGR at the surface with little impact of duration of culture period and higher DGR and biomass yield on coir rope suggest cultivation is possible throughout the year along the southeast Indian coast. The findings of the present study suggest that the cultivation of H. musciformis on coir rope is viable and fisher folk can take up such activities as a part-time income generating activity in southeast Indian coast.