Impact of temperature ,irradiance and photoperiod on biomass and alginate content of sargassum boveanum

Effect of temperature, irradiance and photoperiod on biomass and the alginate content of Sargassum boveanum was evaluated for 42 days under laboratory conditions. The seaweed samples were collected from coast lines of Bandae-e-Lengeh in Hormozgan province (South of Iran) in June 2009. The algae were suspended in aquariums,40.30.60 cm (20 litter) in 3 replicates. The algae were cultured under temperatures gradients ( 15,20 and 25 ºC ), irradiances levels (4700,5700 and 6700 Lux) and three photoperiods (12;12, 14;10 and 16:8 hours, Light:Dark) . The algae were weighted once a week . After 6 weeks of experiments, the algae were collected, dried and weighed. The highest biomass of S. boveanum was obtained at 25° c (48.12 gr.) ,4700 Lux (42.48 gr) 12:12, light: dark (34 gr). Maximum content of alginate (29.67%) was extracted in temperature of 25 ºC. As the results showed, mariculture of this algae should done in spring with optimum of temperature and photoperiod. The alginate content of S. boveanum in this project is high in compare with the other studies.