Asian Journal of Fisheries and Aquatic Research

Seaweed Kappaphycus alvarezii has a high economic value. This seaweed is included in the class Rhodophyceae or red algae which is known for its diverse nutritional content, high vitamin content, protective pigments, and sufficient mineral content, so that this seaweed is widely used in various industries, such as the food industry, health sector, and cosmetics industry. The problem that cultivators often face is limited seeds, so tissue culture seeds are needed. Different seaweed harvest periods will affect the quality produced. From this statement there has been no related research regarding the different lengths of maintenance for seaweed plantlets resulting from tissue culture, especially in Gerupuk Bay. Therefore, it is important to carry out research regarding different lengths of maintenance, with the aim of finding out the optimal harvesting period for cultivators. The method used in this research was an experimental method with a completely randomized design. This treatment was carried out with 4 treatments and 3 repetitions, namely P1: 30 days, P2: 35 days, P3: 40 days and P4: 45 days. The four treatments were repeated 3 times to obtain 12 experimental units. The initial seed weight used in each treatment was 10 grams. The water quality parameter values ​​obtained during the research are still considered optimal. The results of the research carried out can be concluded that the harvest age for seaweed Kappaphycus alvarezii have a real influence on weight growth, specific growth in seaweed. The best absolute growth was obtained in the P4 treatment with a 45 day harvest with a weight of 388 grams, as well as the best specific growth rate in the P4 treatment of 5.91%.