Cultivation of seaweed Kappaphycus alvarezii (Doty) doty ex silva using tissue–cultured seedlings in encircling tank culture system

Abstract

The seaweed, Kappaphycus alvarezii, is the most widely cultivated commodity in Indonesia. The problem currently faced is seedling availability due annual seasonal variations such as heavy flooding This paper presents a study aimed at solving seedling scarcity: the first based on cultivating tissue-cultured seedlings in encircling tanks. The aim of the study was to determine the effect of different initial weight on growth and carrageenan yield of K. alvarezii using tissue – cultured seedlings. This research was conducted from March to June 2019 in the Shrimp Hatchery, Kendari, Indonesia. This study applied three treatments based on different initial weight and five replications. The treatments were 5g, B: 10g and 15 g initial weights (IW). The results showed that the daily growth rate (DGR) of all treatments tended not to differ significantly but the DGR of 5-g IW tended to be higher than those of the other two treatments. The means of DGR were 3.76±0.54%/day, 3.30±0.46%/day, and 2.84±0.27%/day for 5-, 10-, and 15-g IW, respectively. Healthy rates of all treatments were 90.28%, 94.45% and 87.47% for 5-, 10- and 15-g IW. The ratio of fresh weight (FW) and dry weight (DW of 5-, 10-, and 15-g IW were 9.51:1, 9.54:1, and 9.56:1, respectively. The ratio showed no significant differences among treatments. Furthermore, for carrageenan yield, 15-g IW treatment showed the highest yield (37.05±2.18%), but had no significant differences from the other two treatments. Furthermore, all water quality parameters, temperature, salinity, DO, pH, nitrat, phosphate and turbidity were within the normal range for cultivating the seedlings. In conclusion, 5-g initial weight is a prominent weight suitable to be used in cultivating the seedlings in the encircling tank.