<![CDATA[Kappaphycus alvarezii is an important seaweed for various industries. Indonesia, as one of the largest producers, cultivates it extensively in South Sulawesi, particularly on Tanakeke Island. However, because the adoption of aquaculture technologies among local farmers remains limited, the quality and quantity of production are not yet optimal, making the use of biofertilizers one solution to increase cultivation yields. Biofertilizers are necessary because they are environmentally friendly and can be made from industrial waste to improve productivity. However, their effectiveness is not yet known, and the basic materials are very limited. Therefore, this study aims to evaluate the effectiveness of using biofertilizers made from black soldier fly frass (BSFF) and K. alvarezii in increasing the specific growth rate and carrageenan content of K. alvarezii. Water-quality parameters were also measured to support the interpretation of the experimental results. Samples were collected in Mallasoro Bay, South Sulawesi, and laboratory analysis were conducted at Pangkajene Pangkep Island State Polytechnic Laboratory. This research used four treatments: treatment A (BSFF-based biofertilizer), treatment B (K. alvarezii-based biofertilizer), treatment C (combination of BSFF and K. Alvarezii-based biofertilizer), and treatment D (control). The results showed that treatment C had the highest average specific growth rate of 5.41 ± 0.84%. Treatment C also had the highest carrageenan content of 56.61 ± 0.63%. This study highlights the potential of a combination of biofertilizer based on BSFF and seaweed as an environmentally friendly and cost-effective alternative to chemical fertilizers for increasing K. alvarezii cultivation productivity while utilizing BSFF waste. However, commercial use of these biofertilizer combinations requires further study.]]>
