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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. [ABSTRACT FROM AUTHOR]

The commercial cultivation of Kappaphycus alvarezii is the main source of raw material for the carrageenan industry. Brazilian commercial farming uses floating rafts that serve as substrata for fouling organisms that may affect production of the carrageenophyte seedlings. The aim of this work was to identify and quantify the biofouling on floating rafts at Sepetiba Bay, Rio de Janeiro State (23° 02′ 25″ S and 43° 53′ 39″ W), and to evaluate seedling damage caused by epibionts and endobionts. Samples were collected from August 2006 to August 2007. In each assessment, organisms contained in random sampling areas of 18 quadrats of 0.10 m ( n = 18) were removed from floating rafts. K. alvarezii seedling samples were collected to verify the presence of epibionts or endobionts ( n = 30). Twenty-four taxa belonging to seven groups of animals and three groups of seaweed were found. The percentage occurrence estimated 13 dominant organisms and amphipod tubes: e.g., Chondracanthus tedii, Cladophora vagabunda, Gracilariopsis tenuifrons, Hypnea spinella, Hypnea musciformis, Hincksia mitchelliae, Spyridia spp., Ulva spp., Bowerbankia sp., Bugula neritina, Botryllus sp., Haplosclerida sp., and Perna perna. Richness, equitability, diversity, and total biomass varied significantly during the study period ( p < 0.001). There was a tendency for higher biomass values in August 2007. After 6 months, epibionts (i.e., Chlorophyta, Rhodophyta, Chordata, Cnidaria and Ectoprocta) were found on K. alvarezii seedlings. Endobionts were not found in this study. The biofouling biomass was not found to have a significant effect on K. alvarezii daily growth rate, carrageenan yield, or quality (gel strength and viscosity; p > 0.05). [ABSTRACT FROM AUTHOR]

Four strains of Kappaphycus alvarezii were cultivated in the subtropical waters of Florianópolis, Santa Catarina State, Brazil (27°29′19′′ S/48°32′28′′ W), from February 2009 to February 2010. Seaweeds were cultivated on floating raft near of mussel farms. Salinity ranged from 29 to 36 psu and temperature from 17.1 to 28.5°C. Higher growth rates (5.12-4.29% day) were measured in summer and autumn, showing a positive correlation between growth rate and water temperature. Lower growth rates (0.54-0.32% day) occurred in winter, resulted mainly by biomass loss. Significant differences were observed among the strains in spring and the brown tetrasporophytic strain was the only one which failed to recover, being excluded of the experiments. The effect of cultivation periods (36, 42, and 97 days) on carrageenan yield, gel strength, and viscosity were analyzed. Carrageenan yields were higher for plants kept 42 days in the sea (28%), against 25% for 36 and 97 days. There were no significant differences in carrageenan yield among the strains analyzed. Viscosity increased with the increase of cultivation period, while gel strength seemed to vary at random. Tetrasporangia and cystocarps were not observed, and lost fragments did not attach outside the raft. In general, dissolved inorganic nitrogen concentration decreased around the cultivation area as compared to the mussel farm. Results show that cultivation of K. alvarezii is technically feasible in subtropical waters and can be associated with local mussel farms, mitigating the eutrophication and, eventually, increasing the economic return of the farmers. [ABSTRACT FROM AUTHOR]

new cultivation technique for Kappaphycus alvarezii was used in the Brazilian southeastern coast (23°02′25″ S and 43°53′39″ W), the tubular netting on floating rafts. The tubular net technique (TN) was compared with the current method of tie-tie (TT). After 47 days, the daily growth rate (mean ± SD of TN and TT = 3.4 ± 0.7% day), carrageenan yield (mean ± SD of TN and TT = 36 ± 1.3%), gel strength (mean ± SD of TN and TT = 730 ± 114.5 g cm²), and viscosity (mean ± SD of TN and TT = 350 ± 60.4 cP) did not differ between the two techniques ( p > 0.05). The amount of time used to plant (TT = 30.2 ± 2.3 min and TN = 13.3 ± 3.4 min) and to harvest the seedlings (TT = 36.2 ± 2.7 min and TN = 17.8 ± 3.7 min) were lower in TN ( p < 0.001). It is concluded that TN was more effective than TT, the cultivation management (time rates used to plant and harvest the seedlings) was 53.6% faster, no seedlings were lost, the cost was lower, and an estimated return in 1 year of nearly 20% more than that of the TT technique. [ABSTRACT FROM AUTHOR]

The carragenophyte Kappaphycus alvarezii has been introduced into tropical regions, including Brazil, for aquaculture purposes. Our study estimated the biomass loss of farmed cuttings, the establishment of cuttings outside the rafts, the occurrence of spores, and evaluated the invasive potential of K. alvarezii at three sites in Rio de Janeiro state. Temperature, salinity, water transparency, wind velocity and direction (hydrodynamic indicator) and solar radiation (irradiance availability indicator) varied spatially. We found no spores in cultivated cuttings and no verified spore recruitment on artificial substrata. Biomass loss of cuttings varied temporally; however, it was restricted to the cultivation management area of one site and was low compared to native algal biomass. The establishment of cuttings was apparently limited by herbivory at Ilha Grande Bay and controlled by water transparency, hydrodynamics and temperature at Sepetiba Bay. The invasive potential of K. alvarezii was considered remote. However, the use of environmental protocols for cultivation activities is necessary to prevent environmental impacts, mainly in tropical regions. [ABSTRACT FROM AUTHOR]

The carrageenophyte Kappaphycus alvarezii was introduced in 1995 and vegetatively propagated in Ubatuba, São Paulo State, Brazil, for the purpose of commercial cultivation. This species produces tetraspores mainly in the austral summer and fall. Tetraspore germination and survival were studied under different conditions of temperature, photon flux density, and photoperiod in the laboratory. Field experiments were also carried out. Although tetraspores of K. alvarezii germinated, they had low survival rates, most dying after 20 days. Recruitment of K. alvarezii tetraspores did not occur in experiments conducted in the field. The results indicated that the establishment of K. alvarezii via spore production in the natural environment of the south-east coast of Brazil is rather remote. [ABSTRACT FROM AUTHOR]

We compared the growth rates of Kappaphycus alvarezii (Doty) Doty ex P. Silva and Kappaphycus striatum (Schmitz) Doty, both, in vitro under different conditions of light and temperature, and in the sea. Temperature was the most important factor controlling the growth of both species, in vitro and in the field. In the sea there was a clear seasonal pattern in growth rate, attributed to temperature and salinity variation. The lower growth rates were registered in winter and spring, and the highest in summer and autumn months for both species. Based on growth rate in the field, and the production of viable tetraspores during the summer in Kappaphycus striatum, we conclude that is more profitable, and ecologically safer, to only continue with the introduction program of Kappaphycus alvarezii. [ABSTRACT FROM AUTHOR]