Culture of the seaweed, Gracilaria tenuistipitata in brackishwater pond as well as lagoon of Muttukadu, Chennai, Tamil Nadu

In this study, an attempt was made to standardise the method of culture of the seaweed Gracilaria tenuistipitata in brackishwater ecosystems. The species was selected as it is available in abundance due to its tolerance for a wide range of salinity, as seaweed culture in brackishwater ecosystem requires a suitable species which is adaptable and proliferating, An experiment was conducted to estimate the proliferation capacity of G. tenuistipitata with different methods of propagation viz., rope culture and net bag culture with different initial biomass intensity (50, 100 and 200 g m-1 in rope and 50, 100 and 200 g m-2 in net bag) in different ecosystems viz., lagoon and pond. The results showed that G. tenuistipitata proliferates in both lagoon and in pond ecosystem, with high SGR in rope culture compared to net bag method. With respect to different initial biomass intensity in rope method, there was no significant difference in specific growth rate (SGR) between 50 g m-1 (12.86±0.35%) and 100 g m-1 (10.94±0.34%) but it was significantly higher when compared to 200 g m-1 (6.14±1.1%) during 20 days of culture in lagoon ecosystem. It was also observed that SGR was significantly higher with 50 g m-2 (7.23±0.46%) when compared with 100 g m-2 (5.86±0.03%) and 200 g m-2 (5.64±0.02%) in net bag culture in pond ecosystem. Moreover, 20 days of culture showed significantly higher SGR with 50 and 100 g m-1 than 40 and 60 days of culture period in lagoon ecosystem. It can be concluded that rope cultivation of G. tenuistipitata with 50-100 g m-1 of initial biomass intensity was ideal in lagoon for 20 days of culture at brackishwater salinity regime of 19-25 ppt.