Temporal variation of the growth, carrageenan yield and quality of Kappaphycus alvarezii (Rhodophyta, Gigartinales) cultivated at Sepetiba bay, southeastern Brazilian coast

摘要

Kappaphycus alvarezii commercial cultivation is increasing along Brazilian coast. After 2008, more than 30 farms were established at Rio de Janeiro state in Sepetiba and Ilha Grande bays. Each farm has about ten floating rafts corresponding to near 900 m of cultivation line. Understanding the effect of the environmental factors on the growth and carrageenan yield and quality of the target algae in commercial farms will subsidize the establishment of efficient management activities to be used in the farms. In this sense, the temporal variation of the K. alvarezii daily growth rate, productivity, carrageenan yield, and quality (viscosity and gel strength) were analyzed using the seedlings cultivated in the largest Brazilian commercial cultivation at Sepetiba Bay. The daily growth rate, productivity, and carrageenan yield and quality were within the commercial requirement desirable for commercial crops. The main factors that caused the breakage of the floating rafts and consequently diminished the productivity are the storms. Water temperature and salinity were the other factors that influenced the daily growth rate and carrageenan yield and quality.