Growth of Kappaphycus alvarezii Seaweed from Tissue Culture Cultivated with Different Initial Seed Weights

Abstract-Seaweed, commonly called seaweed, is one of the abundant biological resources in Indonesian waters, covering around 8.6% of the total marine biota. The area of ​​seaweed habitat in Indonesia reaches 1.2 million hectares, making it the largest in the world. One type of seaweed that is commonly cultivated is Kappaphycus alvarezii. This study aims to analyze the effect of different initial seed weights on the growth of K. alvarezii seaweed from tissue culture. This study lasted for 45 days, carried out from May to June 2024, located in the waters of Gerupuk Hamlet, Gerupuk Village, Pujut District, Central Lombok Regency, West Nusa Tenggara. Data were analyzed using Analysis of Variance (ANOVA) with a 95% confidence level. If there is a significant effect (significantly different) from each treatment, further testing will be carried out using the Duncan test with the same confidence level. Meanwhile, water quality data and tissue sections were analyzed descriptively. The results of this study indicate that the use of different initial seed weights can increase the absolute weight of K. alvarezii tissue culture results ranging from 27.94g - 49.52g, the specific growth rate ranges from 0.39% - 3.14%. Carrageenan yield ranges from 0.37% - 0.54%. Seaweed production ranges from 307.2 - 998.2 g / m². The tissue structure of K. alvarezii seaweed with different seed weights obtained the results of P1 (25g) showing the results closest to the tissue structure before maintenance. The measurement of water quality during the study including salinity, pH, temperature, and phosphate was still ideal while light intensity and nitrate were not ideal for K. alvarezii seaweed cultivation. This study concludes that K. alvarezii seaweed cultivation with different initial seed weights can affect the specific growth rate but does not affect the absolute weight.