Effect of Depth on the Growth and Carrageenan Content of Seaweed Kappaphycus alvarezii Cultivated Using Verticulture Method

Abstract

Seaweed of Kappaphycus alvarezii is generally cultivated by the long line method through the water surface. The verticulture method might be an alternative method by using water column. This research aimed to evaluate the effects of depth on the growth and carrageenan content of K. alvarezii which was cultivated vertically. Cultivation was carried out in the floating raft (10 x 10 m)2 contained of 36 vertical nets. The size of each net was 5 x 2 m2 whereas the depth was 0.2, 1, 2, 3, 4, and 5 m. Seaweed seedlings of 50 g was each tied to the vertical nets; the distance between the knot was 20 cm. The results showed that the depth was significantly different to the daily growth rate of K. alvarezii (p<0.05) but did not affect carrageenan content (p>0.05). Therefore, this method might be applied as an alternative method to optimally increase seaweed production in narrow area without affecting seaweed quality.