Edison José de Paula

Growth rate and carrageenan analyses in four strains of Kappaphycus alvarezii (Rhodophyta, Gigartinales) farmed in the subtropical waters of São Paulo State, Brazil

Growth rate, semi-refined and refined carrageenan yields, 3,6-anhydrogalactose and sulphate contents, and gel strength were investigated in four strains of Kappaphycus alvarezii (brown, green and red tetrasporophytic strains, and one strain derived from tetraspores progeny, called G11) farmed in subtropical waters of São Paulo State, Brazil. All studied strains showed higher growth rates from February to May, decreasing from July to December. The G11 strain exhibited lower growth rates, but had semi-refined and refined carrageenan yields significantly higher than the others and similar to a commercial sample. A negative correlation between growth rate and semi-refined carrageenan yield was verified for all strains. The brown strain had the lowest content of 3,6-anhydrogalactose, while G11 and green strains showed higher values. No clear pattern of variation and no relationship were observed for sulphate and gel strength. However, all strains presented gel strength values near the one obtained from commercial sample. These results show that the carrageenan extracted from brown, green, red, and G11 strains of K. alvarezii cultured in subtropical waters of São Paulo State, Brazil with commercial potentials.

Strain selection in Kappaphycus alvarezii var. alvarezii (Solieriaceae, Rhodophyta) using tetraspore progeny

A brown strain of Kappaphycus alvarezii from the Philippines produced tetraspores in the summer and autumn (December 1995 to May 1996) in cultivation experiments in the sea at Ubatuba, São Paulo State, Brazil. In vitro tetraspore release and germination experiments showed a mass mortality two to four days after release. Only 20 plants derived from tetraspores were grown successfully for over a year in the laboratory. Large differences in morphology, colour, size and growth rates were observed amongst these plants. The individual plants differed from one another in one or more characteristic. Differences appeared in the early developmental stages and persisted through time. After ten months, the plants that grew best in laboratory culture were transferred into the sea, but the others remained very small (3 to 5 mm), even after two years. In the sea, the plants also showed individual differences in their ability to survive and grow. These results emphasise the potential of the tetraspore progeny for strain selection in K. alvarezii. The results also suggest that the tetrasporophyte used in these studies is of hybrid origin.

Growth rate of the carrageenophyte Kappaphycus alvarezii (Rhodophyta, Gigartinales) introduced in subtropical waters of Sao Paulo State, Brazil

Twenty branches of Kappaphycus alvarezii (Doty) Doty ex P. Silva produced in unialgal culture and weighing about 3 g each were transferred into the sea monthly from October 1995 to October 1996 at Ubatuba Bay, São Paulo State, Brazil (23°26.9′S, 45°0.3′W), an area with mean monthly seawater temperature from 20.3 to 28.5°C (extremes: 17.0–31.0°C). All plants were harvested after the second month and a new series of growth experiments was performed using cuttings weighing from 100 to 150 g. The cultivation experiments were carried out using a floating system. Daily growth rates were calculated based on monthly weight measurements of each individual. Small branches produced in vitro showed high survival rates when introduced into the sea during all seasons. Growth rates observed for the transplanted branches during the first and second months in the sea were higher (6.5–10.7% day‐1) than for subsequent cuttings produced in the sea (4.5–8.2% day‐1). The latter values are in the range reported for other regions. Seasonal variation of growth rates was clearly related to seawater temperature. These results show that the commercial cultivation of K. alvarezii is technically feasible at Ubatuba Bay using a floating raft culture method.

Padrões estruturais quantitativos de bancos de Sargassum (Phaeophyta, Fucales) do litoral dos estados do Rio de Janeiro e São Paulo, Brasil

This paper aimed to describe the biological structure of Sargassum beds along the coasts of Rio de Janeiro and Sao Paulo states. Sixteen rocky shore communities were sampled at random (50 x 50 cm quadrats) during 1991-92. These communities presented populations of distinct Sargassum species. They were chosen because they were subjected to different degrees of wave action and emersion. Seven infrageneric taxa of this genus were studied. The Sargassum dry mass varied from 37 g.m-2 to 587 g.m-2; the highest values were found in moderate and protected sites. The cluster analysis of these communities, considering the dry mass of 75 groups of macroalgae and macroinvertebrates, indicated three structural patterns characterized by the most abundant group of organisms: 1) Sargassum, in places not exposed to direct wave action, frequent emersion nor recent disturbances; 2) calcareous algae (Corallinaceae), mainly in exposed places, with Phragmatopoma lapidosa (tube worm) and/ or Perna perna (mussels); 3) other groups of non-calcareous algae, such as Dictyopteris delicatula, representative in intermediate situations. These patterns may be usefull to study the exploitation potentiality of Sargassum and other organisms, like mussels, in the Brazilian coast.

Introduction of non‐native species of Kappaphycus (Rhodophyta, Gigartinales) in subtropical waters: Comparative analysis of growth rates of Kappaphycus alvarezii and Kappaphycus striatum in vitro and in the sea in south‐eastern Brazil

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.

Germination and survival of tetraspores of Kappaphycus alvarezii var. alvarezii (Solieriaceae, Rhodophyta) introduced in subtropical waters of Brazil

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.

Growth rate of the carrageenophyte Kappaphycus alvarezii (Rhodophyta, Gigartinales) in vitro

Unialgal cultures were established trom a 2.5 g branch ot a brown variant ot Kappaphycus alvarezii (Doty) Doty ex P. Silva, with the main objective to produce branches for monthly outplanting in the sea. Ditterent conditions were tested to optimize production ot branches in the laboratory. The best growth was obtained under culture conditions of 25 ± 2°C, 170–210 μmol photons m2 s−1, 14:10 LD photoperiod and salinity 32–35‰. Three culture media (Provasoli,‘F/2’and von Stosch) were tested. Deleterious ettects were observed in branches incubated continuously in full‐ or halt‐strength Provasolis enriched seawater medium (PES). Exponential growth rates ot about 3% day−1 were obtained using PES, pulse‐fed 24 h per week, or other diluted media used continuously (one‐quarter strength ‘F/2’and half‐strength von Stosch). Laboratory‐grown branches with mean weights from 2.97 to 4.25 g were successfully introduced into the sea at Ubatuba, SP, Brazil (23°26.9′S, 45°0.3′W) an area with mean monthly seawater temperature from 20.3 to 28.5°C (extremes: 17.0–31.0°C). Transplantation of branches produced in unialgal culture, as done in the present study, avoids the risk of introduction of unwanted species into new areas.

Intraspecific variation in Gracilaria birdiae (Gracilariales, Rhodophyta): growth, and agar yield and quality of color strains under aquaculture

Abstract Based on their distinct physiological characteristics, we postulated that different strains of Gracilaria birdiae (Gracilariales, Rhodophyta) would have distinct performances when grown in the sea. Samples from a northeastern Brazil population, including red (RD-CE), greenish-brown (GB-CE), and green (GR-CE) strains, and one red strain (RD-ES) from a southeastern population were cultivated in Ubatuba Bay, southeastern Brazil. We analyzed the survival ability, growth rate, and the agar yield and quality of these strains. The growth rates (GRs) and seawater temperatures were measured for 16 months. The northeastern population strains were in good condition during all the cultivation periods, while the RD-ES strain had a lower GR and died during some time periods. Overall, the GR ranged from 0.4% to 4.4% day-1, depending on the strain and the period of cultivation. The GRs of the RD-CE, GR-CE, and GB-CE strains were similar during all the cultivation periods. The increased GR in all the strains of G. birdiae seemed to be related to a slight rise in the seawater temperature. However, the GRs decreased in all the strains when the temperatures remained high for the protracted periods. In addition to their similar GRs, the RD-CE and GR-CE strains had similar yields and qualities as the polysaccharides. We concluded that these three strains are suitable for testing as the candidates for future commercial cultivation.