Laboratory culture of Gracilaria spp. and Ulva lactuca in seawater enriched media

Thallus bits of Gracilaria edulis, G. corticata, G.crassa and Ulva lactuca were maintained in three enriched seawater growth media under laboratory conditions. Weekly observation on growth rate of these algae showed that Walne's medium enhanced Daily Growth Rate (DGR) of Ulva lactuca (54.42 f 3.82 mg/d), Gracilaria corticata (58.71 f 3.35 mg/d) and G. crassa (72.42 f 2.07 mg/d). Gran'laria edulis registered higher growth rate in PES medium (50.42 f 3.82 mg/d) than in Walne's and Gamborg media. However, addition of 2% garden soil extract to Walne's medium promoted the DGR in all the four species considerably (62.28 mg/d for Ulva, 66.71 mg/d for Gracilaria corticata, 77.71 mg/d for G. crassa and 56.29 mg/d for G. edulis). The results are compared with the growth rate of seaweeds achieved elsewhere in in situ sea farming being carried out without addition of any nutrients extraneously.