Identification and determination of optimum growth condition with respect to selected environmental parameters for open sea cultivation of Gracillaria edulis in Andaman water

Gracilaria edulis is one of India's most widely cultivated seaweeds. Pilot scale cultivation of Gracilaria edulis was initiated at Andaman, India for the first time. In the present study attempt has been made to identify how different water quality parameters influence the growth. Total 11 physicochemical parameters and 9 microbiological parameters, as well as chlorophyll and zooplankton, phytoplankton parameters were studied for two different seasons to evaluate which parameters influence seaweed growth. Six (nitrate, nitrite, ammonia, silicate, chlorophyll, photosynthetic active radiation) have a positive impact on seaweed growth, while some of the bacterial species showed negative impact. Lowess 3D curve fit model showed pH range from 7.59 to 7.82, N/P ratio of 2.046, rainfall 23.85–24 mm, and Photosynthetic active radiation of 376.6 W/m2 are optimum for Gracillaria growth. This model can be applied to future mass culture. [Display omitted] •Gracillaria Edulis is cultivated for both Food and industrial purpose.•Water quality parameters such as Nutrient and bacteria influence growth.•Multiple parameters are positively correlated with seaweed growth.•Optimum value for selected parameters determined•Interaction between the Biological and Physicochemical parameters are important for growth.