The growth model of Eucheuma cottonii cultivated in Karimunjawa Islands, Indonesia

Seaweed cultivation has a strategic role in fisheries development in Indonesia. Indonesia is the second largest seaweed producer in the world. Seaweed cultivation is relatively easy and low-cost. Therefore, there are many coastal communities in the small islands that culture it, including in Karimunjawa Islands. Thus, seaweed cultivation has a large contribution to the economy of coastal communities. The most cultivated species of seaweed in Indonesia is Eucheuma cottonii. The purpose of our research was to develop the growth model of Eucheuma cottonii cultivated in Karimunjawa Islands. We used 9 (nine) observation (basket) units that were measured the growth weekly for 42 days. Our research location was on the coastal waters of Kemojan Village, Karimunjawa Islands. This research has proven that the polynomial growth model has the largest R2 compared to the exponential model and the linear model. Based on polynomial growth model, the growth of E. cottonii follows the equation: Y = -0.29t2 + 49.73t + 1969.3 (R2 = 0.9967) that Y is the biomass of seaweed and t is the day of culture. This growth model can be used to estimate the seaweed biomass and profit related to the harvest time.