Now showing items 1-10 of 10

    • Article

      Agar production from Gracilariopsis heteroclada (Gracilariales, Rhodophyta) grown at different salinity levels 

      AQ Hurtado-Ponce - Botanica Marina, 1994 - Walter de Gruyter
      Gracilariopsis heteroclada grown in fiber glass tanks at four salinity levels was treated with three different concentrations of aqueous NaOH. Yield, gel strength, gelling and melting temperatures of the extracted agar were determined. Plants grown at salinities of 24 and 32 ppt and treated with 3% NaOH produced the strongest gel (850 g cm-2) and weakest gel (300 g cm-2), respectively. Statistically significant differences in gel strength, dynamic gelling and melting temperatures were observed between the various treatments. The interactive effect of salinity and NaOH was significant in gel strength, gelling and melting temperatures of the gel from G. heteroclada.
    • Article

      Assessment of some agarophytes from the coastal areas of Iloilo, Philippines. I. Seasonal variations in the biomass of Gracilaria changii, Gracilaria manilaensis and Gracilariopsis bailinae (Gracilariales, Rhodophyta) 

      HB Pondevida & AQ Hurtado-Ponce - Botanica Marina, 1996 - Walter de Gruyter
      Monthly biomass (g dwt m-2) of Gracilaria changii, G. manilaensis and Gracilariopsis bailinae collected in four different coastal areas of Iloilo, Philippines showed significant differences. Gracilaria changii (3.0-32.4 gm-2) and G. manilaensis (8.9-35.7 gm-2) were present only for six and three months respectively during the dry season. Gracilariopsis bailinae was present year-round at both sites, however, its abundance was not uniform, being abundant during the wet season in Estancia (13.4-119.3 gm-2) and during the dry season in Zarraga (6.9-43.5 gm-2). Except for rainfall and level of phosphate, all environmental factors (temperature, salinity, pH, turbidity, NO2-N and NH2-N) showed insignificant relationship with the biomass of each species.
    • Article

      Assessment of some agarophytes from the coastal areas of Iloilo, Philippines. II. Seasonal variations in the agar quality of Gracilaria changii, Gracilaria manilaensis and Gracilariopsis bailinae (Gracilariales, Rhodophyta) 

      HB Pondevida & AQ Hurtado-Ponce - Botanica Marina, 1996 - Walter de Gruyter
      Three species of agarophytes (Gracilaria changii, G. manilaensis and Gracilariopsis bailinae) collected along the mud flats of Iloilo were investigated to determine the monthly variation in agar yield (%), gel strength (g cm-2), gelling and melting temperatures (°C) and sulfate content (µg mg-1). Results show that Gracilariopsis bailinae collected at Zarraga gave a higher gel strength (784 g cm-2) than that collected at Estancia (637 g cm-2), however, the latter gave a higher agar yield (22%). A year-round source of agar was demonstrated in G. bailinae in both places while Gracilaria changii (January to June) and G. manilaensis (April to June) were seasonal. Higher agar yield and gel strength were measured from G. changii than in G. manilaensis. Gracilariopsis bailinae showed agar qualities superior to those of the two other species, hence it is a good species to harvest and develop for mariculture and consequently for agar manufacture.
    • Article

      Assessment of the seaweed-seagrass resource of Mararison Island, Culasi, Antique, Philippines 

      AQ Hurtado-Ponce, EAJ Chavoso & NP Parami - Phycological Research, 1998 - Japanese Society of Phycology
      A bimonthly sampling of the seaweed-seagrass resource of Mararison Island, Culasi Antique, was undertaken over 1 year to assess the species composition, similarity of taxa, and biomass (dry weight [d.w.] g m−2) at seven localities. A total of 45 species was identified: 17 Chlorophyta, seven Phaeophyta, 15 Rhodophyta, one Cyanophyta and five seagrasses. Except for some Rhodophyta and Syringodium isoetifolium (Ascherson) Dandy, the occurrence of species between stations was not significantly different; however, differences in biomass between sampling time (month) were significant. Identical taxa between stations were determined. The highest (40) and lowest (22) number of species collected were in May and July, respectively. The species were most abundant from March to May (dry months) and sparse from July to September (wet months). The most abundant species were: Sargassum polycystum C. Agardh (399 g m−2) (Phaeophyta), Dictyosphaeria cav-ernosa (Forsskat) Borgesen (43.1 g m−2) (Chlorophyta), Acanthopeitis japonica Okamura (97.2 gm−2) (Rhodophyta) and Thalassia hemprichii (Ehrenberg) Ascherson (1370 g m2; seagrass). The Phaeophyta were abundant in March, and the Chlorophyta and Rhodophyta in May, while the seagrasses were abundant in September. Some species occurred only during the dry months: two Phaeophyta, nine Chlorophyta and five Rhodophyta. All the seagrasses were found year-round. Almost all of the seaweeds (39/45) were found associated with seagrass. The number of seaweeds in Mararison Island was higher than for seagrasses but the total biomass of the latter was much higher than the combined biomass of the seaweeds.
    • Article

      Economics of cultivating Kappaphycus alvarezii using the fixed-bottom line and hanging-long line methods in Panagatan Cays, Caluya, Antique, Philippines 

      AQ Hurtado-Ponce, RF Agbayani & EAJ Chavoso - Journal of Applied Phycology, 1996 - Springer Verlag
      A socio-economic survey was conducted among the Kappaphycus alvarezii planters of Panagatan Cay, Caluya, Antique, Philippines to determine some social information, farming practices and cost and returns of farming the seaweed. Cultivation is dominated by brown and green morphotypes using the fixed-bottom and hanging-long line methods. Approximately 9.3 t d. wt ha−1 and 7.2 t d. wt ha−1 is produced from fixed-bottom and hanging-long lines methods, respectively, after 60–90 days of culture. The former method requires a working capital and total investment of P7490 and P1870, respectively, compared to the hanging-long line which requires P8455 and P25464, respectively (US$ 1 = P26). A higher total revenue (P139500), net income ((P187895), and return of investment 1002%), but a shorter pay back period (0.10 years) were obtained in fixed-bottom than in hanging-long line. A lower total expenses were incurred in fixed-bottom (P21354) than in hanging-long line (P24566). The farming of K. alvarezii in this area has brought tremendous economic impact to the marginal fishermen.
    • Article

      Gathering of economically important seaweeds in Western Visayas, Philippines 

      AQ Hurtado-Ponce, MRJ Luhan & NG Guanzon Jr. - The Philippine Scientist, 1992 - San Carlos Publications
      A survey was conducted in 12 coastal municipalities of Western Visayas, Philippines from March to July 1990 to determine the seaweed gathering practices of fishermen. There were 83 gatherers involved in this small-scale industry, who live below the poverty line and who consider it as the number one minor source of income. Only seaweeds of commercial value are gathered in big volume. There were approximately 114 T year-1 of seaweeds harvested from natural stock with a market value of P414, 950.00 ($14,819.64). The harvest is broken down into 3 main groups: (1) agarophytes, 99.5 T (Gelidiella, Gracilaria and Gracilariopsis), (2) carrageenophytes, 10 T (Eucheuma and Kappaphycus) and (3) table vegetable, 10 T (Caulerpa). An average maximum income of P5,600.00 or $200 gatherer-1 season-1 is derived from seaweed gathering.
    • Article

      Growth rate, yield and economics of Gracilariopsis bailinae (Gracilariales, Rhodophyta) using fixed bottom long-line method 

      AQ Hurtado-Ponce, RF Agbayani & GP Samonte-Tan - Philippine Journal of Science, 1997 - Science and Technology Information Institute
      Vegetative thalli of Gracilariopsis bailinae weighing 10 g each were tied to a 5-m monofilament line with plastic strips and laid horizontally on the substrate and were observed to grow at 30 d interval for 9 months. The monthly growth rate and yield were determined and a cost and return analysis of the culture system was made. The monthly growth rate of the seaweed was significantly different (P=0.05) over culture month. The highest average growth rate was 6.7 percent/day while the lowest was 1.7 percent. The lowest and highest average yield (dry wt) was 72 g and 660 g m-2 mo-1, respectively.

      A capital asset of P1,680, working capital of P2,980, and annual production cost of P5,860 were calculated from the culture system. An annual net returns of P31,292 was computed based on a 1,000 m2 area. Return on investment is 671.50 percent while payback period is 1.7 months.
    • Article

      Harvesting Gracilariopsis heteroclada (Gracilariales, Rhodophyta) in Iloilo, Philippines 

      AQ Hurtado-Ponce - Philippine Journal of Science, 1993 - Science and Technology Information Institute
      Gracilariopsis heteroclada thalli were planted in a 1 m2 ditch along a drainage canal at Leganes, Iloilo, Philippines. Monthly growth rate and production were calculated to determine the effect of harvesting on the regeneration capacity of the plant. After 30-day growth period, all plants were harvested at 25%, 50%, 75%, and 100% of the total available biomass. Though highest growth rate was observed at 100% (8.7%), it took three months for the plants to regenerate and obtain a considerable biomass. Positive growths were obtained when plants were harvested at 75% (5.6%) during the entire growth period. Negative growth rates observed both at 25 and 50% harvests.
    • Article

      Laboratory manipulation of Gracilariopsis bailinae Zhang et Xia (Gracilariales, Rhodophyta) 

      SF Rabanal, R Azanza & A Hurtado-Ponce - Botanica Marina, 1997 - Walter de Gruyter
      Carpospore germination, carposporeling development and tetraspore formation were investigated in Gracilariopsis bailinae Zhang et Xia by manipulating photoperiod, photon flux density, temperature, salinity and nutrients. Laboratory-generated sporelings attained mean growth rate from 4.05 to 10.31% d-1 during the first week of incubation. Duncan s multiple range test (DMRT) showed that growth rates were significantly different (P < 0.05) between the treatment combinations and between weekly intervals. The optimal condition for growth of sporelings, irrespective of culture age, was attained at treatment combinations of 26°C, 11:13 (h. L:D) photoperiod, 100 µEm-2s-1 photon flux density (PFD), 25 µM NH4Cl: 2.5 µM K2HPO4 and 25ppt salinity followed by a treatment combination of 26°C, 11:13 (h. L:D) photoperiod, 100 µEm-2s-1 photon flux density (PFD), 50 µM NH4Cl: 5 µM K2HPO4 and 25 ppt salinity. For the first time in this species, tetraspore formation was induced in the laboratory. The tetrasporophyte produced many tetraspores in almost all branches of the thallus grown at 26°C, 11:13 (h. L:D) photoperiod, 100 µEm-2 s-1, 25 µM NH4Cl: 2.5 µM K2HPO4 and at 30 ppt salinity while those grown at lower light, higher nutrient level and higher salinity had fewer tetraspores. No tetraspores were formed at a higher temperature (30°C), longer photoperiod (13:11 h. L:D), and at 25 ppt salinity and the plants remained vegetative from 4 to 7 months. Logistic regression analysis showed that tetrasporangial induction was significantly affected by nutrients and salinity (P < 0.05).
    • Article

      Rheological properties of agar from Gracilariopsis heteroclada (Zhang et Xia) Zhang et Xia (Gracilariales, Rhodophyta) treated with powdered commercial lime and aqueous alkaline solution 

      AQ Hurtado-Ponce - Botanica Marina, 1992 - Walter de Gruyter
      Rheological properties were measured for 1.5% agar gels from Gracilariopsis heteroclada pre-treated with powdered commercial lime (CaCO3) during sun drying, and a combination of two alkaline solutions during water-bath heating in the laboratory. All samples were subjected to a one or three hours of heating prior to extraction.

      Slightly higher agar yield were obtained from samples treated with lime while drying (2.9-4.5%) than from seaweed (2.1-3.8%) treated with alkaline solutions in the laboratory. Better rheological (breaking strength,cohesiveness, breaking energy, and rigidity) and physical properties (dynamic gelling and melting temperatures) were obtained from laboratory treated seaweed after a 3-hour treatment.

      No effect of collection site, alkali treatment and treatment time on the yield of agar, was observed. However, significant (P ≤ 0.01) effects were recorded for collection site, alkali treatment and treatment time both on rheological properties and on gelling and melting temperatures.