Now showing items 1-7 of 7

    • Article

      Growth and carrageenan quality of Kappaphycus striatum var. sacol grown at different stocking densities, duration of culture and depth 

      AQ Hurtado, AT Critchley, A Trespoey & G Bleicher-Lhonneur - Journal of Applied Phycology, 2008 - Springer Verlag
      Kappaphycus striatum var. sacol was grown in two separate studies: (1) at two stocking densities, and (2) at four different depths, each for three different durations of culture (30, 45 and 60 days) in order to determine the growth rate of the seaweed and evaluate the carrageenan content and its molecular weight. The results demonstrated that stocking density, duration of culture and depth significantly (P < 0.01) affected the growth rate, carrageenan content and molecular weight of K. striatum var. sacol. Decreasing growth rate was observed at both stocking densities and at four depths as duration of culture increased. A lower stocking density (500 g m–1line–1) showed a higher growth rate for the shortest durations, i.e. 30 days, as compared to those grown at a higher density. Likewise, decreasing growth rate was observed as depth increased, except at 50 cm after 60 days of culture. A 45-day culture period produced the highest molecular weight at both stocking densities (500 g m–1line–1 = 1,079.5 ± 31.8 kDa, 1,000 g m–1line–1 = 1,167±270.6 kDa). 'Sacol' grown for 30 days at 50 cm (1,178 kDa) to 100 cm (1,200 kDa) depth showed the highest values of molecular weight of carrageenan extracted. The results suggested that K. striatum var. sacol is best grown at a stocking density of 500 g m–1line–1, at a depth of 50-100 cm, and for a duration of 30 days in order to provide the highest growth rate, carrageenan content and molecular weight.
    • Article

      Growth, agar yield and quality of selected agarophyte species from the Philippines 

      KG Araño, GC Trono Jr., NE Montaño, AQ Hurtado & RD Villanueva - Botanica Marina, 2000 - Walter de Gruyter
      Three local agarophyte species (Gracilaria firma, Gracilaria sp. and Gracilariopsis bailinae) were grown under controlled outdoor flow-through culture conditions. Growth rates and agar characteristics of the three species were determined. Gracilaria firma showed superior growth and agar quality among the three species. It exhibited the highest growth rate, highest agar gel strength and was observed to be highly resistant to epiphytes. Growth experiments under various light and ammonium combinations showed that the highest photon flux density level (900 μ mol m−2s−1) and moderate ammonium (150 μM NH4Cl) concentration gave the highest growth rates for all species. The single and interactive effects of light and ammonium enrichment on growth and agar characteristics of the three species were highly significant.
    • Article

      Occurrence of Polysiphonia epiphytes in Kappaphycus farms at Calaguas Is., Camarines Norte, Phillippines 

      AQ Hurtado, AT Critchley, A Trespoey & GB Lhonneur - Journal of Applied Phycology, 2006 - Springer Verlag
      This paper describes the occurrence of an epiphyte infestation of Kappaphycus farms in Calaguas Is. Camarines Norte, Philippines. In particular, percentage cover of ‘goose bump’-Polysiphonia and ‘ice-ice’ disease, and some environmental parameters that influence the thallus condition of Kappaphycus alvarezii in Calaguas Is. were assessed during 3 separate visits and are discussed.

      Commercial cultivation of Kappaphycus at Calaguas Is. began in the early 1990s. After five years of farming, the stock was destroyed by a strong typhoon. The area was re-planted the following year and production increased annually and reached its peak in 1998–1999. However, the following year, the first occurrence of a Polysiphonia epiphyte infestation occurred concurrently with an ‘ice-ice’ disease. Consequently, annual production and the number of seaweed planters declined rapidly, and this situation persists to the present time. This paper highlights the etiological factors and their consequences.

      Results show that farm-site selection is critical for the success of Kappaphycus production. Characteristics of water movement and light intensity in farming areas contributed to the occurrence and detrimental effect of the phenomenon described as ‘goose bumps’: a morphological distortion of the host seaweed due to the presence of a Polysiphonia sp. epiphyte. A strong inverse correlation was observed between the occurrence of Polysiphonia and water movement: areas with low water motion registered a higher % cover (65%) of Polysiphonia than those in more exposed areas (17%). Although ‘goose bump’-Polysiphonia infestation and ‘ice-ice’ disease pose a tremendous problem to the seaweed farmers, the results of this limited assessment provide a useful baseline for future work.
    • Article

      Plantlet regeneration of Kappaphycus alvarezii var. adik-adik by tissue culture 

      AQ Hurtado & AB Biter - Journal of Applied Phycology, 2007 - Springer Verlag
      Three color morphotypes of Kappaphycus alvarezii var. adik-adik (brown, green and red) collected from a farming area in Tictauan Is., Zamboanga City, Philippines were used as explants in the study in order to micropropagate ‘new’ plants. Individual sections of sterile Kappaphycus alvarezii var. adik-adik, initially cultured in a 48-well culture plate containing ESS/2 + E3 + PGR, released callus cells after 4–5 days of incubation at 23–25°C, 13:11H LD cycle and 10–15 μmol photons m−2 s−1 light intensity. True calli were formed after 29–35 days following dense formation of filaments or undifferentiated round cells at the medullary and inner cortical layers of the section. Plantlets (2–3 mm long) of Kappaphycus alvarezii var. adik-adik were able to regenerate after 98, 150 and 177 days in-vitro among the reds, greens, and browns, respectively. This study established successful methods for the production and regeneration of tissue explants of Kappaphycus alvarezii var. adik-adik which can possibly be used to mass produce ‘new’ cultivars for land- and sea-based nurseries as sources for commercial farming.
    • Article

      A preliminary summary on Kappaphycus farming and the impact of epiphytes 

      AT Critchley, D Largo, W Wee, G Bleicher L'honneur, AQ Hurtado & J Schubert - Japanese Journal of Phycology, 2004 - Japanese Society of Phycology
      The read seaweed Kappaphycus alvarezii (Doty) Doty ex. P.C. Silva, commonly called "cottonii" in the processing industry, is used as raw material for the production of the hydrocolloid kappa carrageenan. Through biotechnological advaces, certain carrageenan-producing seaweeds have been truly "domesticated" and are now successfully farmed as marine crops in a number of suitable areas of the world. Significant and sustainable employment opportunities are generated by these activities with few environmental impacts. In mid-2001, the incidence of very heavy epiphytism of cultivated raw material of K. alvarezii (cottonii) was reported for a production centre in the Philippines. This case of epiphytism was "unusual" in that it had been present for a considerable period of time and following epiphyte growth, the seaweed crop began to rot and fall off the cultivation lines (this was not the case of the disease "ice-ice"). The outbreak of the epiphyte infestation followed successional development of an epiphyte community and resulted in a climax population of the read seaweed Polysiphonia sp. This was observed to be preceded by heavy precipitation with consequent siltation reaching the farm site. The presence of the Polysiphonia sp. gave the plants a "hairy" appearance. Where the Polysiphonia was attached, the host plant seemed to produce "galls". The end result was that the Kappaphycus material rotted, fragmented and fell off the cultivation lines. The impact of this epiphyte attack was economically, socially and ecologically serious in that the farmers became disillusioned and either moved from the islands to other cultivation sites, leaving their families behind, or returned to the environmentally damaging practices of dynamite and or cyanide reef fishing. This paper outlines the events of epiphytic settlement and subsequent decomposition of the crop plants. The impact of Kappaphycus farming in the north-east Philippines is outlined as well as steps undertaken to improve the farming practice and enable farmers to return to the sustainable activity of seaweed farming.
    • Article

      Sargassum studies in Currimao, Ilocos Norte, Northern Philippines I. Seasonal variations in the biomass of Sargassum carpophyllum J. Agardh, Sargassum ilicifolium (Turner) C. Agardh and Sargassum siliquosum J. Agardh (Phaeophyta, Sargassaceae) 

      AQ Hurtado & AR Ragaza - Botanica Marina, 1999 - Walter de Gruyter
      Three species of Sargassum (S. carpophyllum, S. ilicifolium and S. siliquosum were collected each month for a period of one year from the inter- and subtidal zones of Pangil, Currimao, Ilocos Norte, The Philippines. Average monthly biomass was species-specific and significantly influenced by the effect of fertility states of the seaweed, collecting zone, and collecting months. A higher biomass of reproductive plants was accounted for in all species in both zones. Among the three species, S. siliquosum had the highest reproductive and vegetative biomass in both zones, followed by S. carpophyllum and S. ilicifolium. Maximum fertility was observed in October for S. carpophyllum and in November for S. ilicifolium and S. siliquosum. Minimum and maximum reproductive biomass was recorded in May and December, respectively in all species. Biomass of vegetative or non-fertile plants was highest in September in all species except for S. carpophyllum, while minimum biomass was recorded in March for S. carpophyllum and May for S. ilicifolium and S. siliquosum. Reproductive plants had more biomass than vegetative plants.

      The average monthly wet biomass (g m−2) of other Sargassum species was higher in the subtidal than in the intertidal zone. The biomass of seaweeds associated with Sargassum did not follow a definite pattern. Although water temperature, pH and salinity values were relatively constant, slight variations of temperature were positively correlated (P = 0.05) with subtidal biomass.
    • Article

      Sargassum Studies in Currimao, Ilocos Norte, Northern Philippines II. Seasonal Variations in Alginate Yield and Viscosity of Sargassum carpophyllum J. Agardh, Sargassum ilicifolium (Turner) C. Agardh and Sargassum siliquosum J. Agardh (Phaeophyta, Sargassaceae) 

      AR Ragaza & AQ Hurtado - Botanica Marina, 1999 - Walter de Gruyter
      The yield (%) and viscosity (cps) of alginate from Sargassum carpophyllum, S. ilicifolium and S. siliquosum collected along the inter- and subtidal zones of Currimao, Ilocos Norte were determined monthly for a period of one year. Results show that each species demonstrated an individual pattern of alginate characteristics which is significantly influenced by the collecting zone, fertility state, and collecting month (P < 0.05). Positive correlations were observed in alginate yield and viscosity with species and fertility states. Among the three species, S. ilicifolium is the best species for alginate production for the food industry based on viscosity characteristics, followed by S. siliquosum and S. carpophyllum.