A Study on the Use of Ocean Fertilizer for Culture of Seaweed

The use of ocean fertilizer containing 20% ferrous sulfate, for the culture of the red alga, K. appaphycus alvarezii, in 50 m² floating raft was evaluated. Two levels of fertilizer application, 1 and 2 kg.wk⁻¹, for a culture period of 60 days were tested. The efficiency of the fertilizer application using perforated plastic bags attached to the rafts was determined. The cost-effectiveness of the use of the fertilizer was also analyzed. Results showed that the application of ocean fertilizer at 2 kg.wk⁻¹ gave the highest net yield of the seaweed that was 30% more than that of the control. The method of fertilizer application was found to be efficient. Considering the net yield of the seaweed and carrageean content, and the cost of the fertilizer, analysis showed that use of the fertilizer is highly cost-effective. Finally, author discusses a new possibility of ocean space use as a culture ground.