Now showing items 1-15 of 15

    • Article

      Deep-sea farming of Kappaphycus using the multiple raft, long-line method 

      AQ Hurtado & RF Agbayani - Botanica Marina, 2002 - Walter de Gruyter
      Farming practices of Kappaphycus seaweed planters using the multiple raft, long-line method were assessed in three major cultivation areas of Zamboanga del Sur, Mindanao. Results show that this cultivation method is appropriate in deeper waters (> 10 m deep). Family labor (6–70 years old) is usually used in the selection and preparation of ‘cuttings’, unloading of newly harvested crops and drying of seaweeds, while preparation and installation of the raft, tying of ‘cuttings’ and harvesting, hired labor is needed. Though the multiple raft, long-line method of cultivating Kappaphycus is expensive (PhP 45,742 to PhP 49,785) based on a 500 m2 raft, return on investment (ROI) is high and the payback period is short. Of the three areas assessed, Maasin had the highest ROI (218%), followed by Tictauan Island (212%), and finally Taluksangay (79%). Consequently, the payback period followed the same order. Seaweed farming in these areas showed a tremendous impact on the quality life of the fisher folk and contributed a high revenue to the national economy.
    • Book

      The farming of the seaweed Kappaphycus 

      AQ Hurtado & RF Agbayani - 2000 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 32
      A 24-page manual that introduces the carrageenan-producing seaweed Kappaphycus whose culture has spread from Jolo in Mindanao to at least 14 sites in the Visayas and Luzon. Four culture methods are presented: fixed off-bottom, raft long-line (single or multiple), hanging long line, and polyculture of seaweeds with carnivorous fishes.
    • Article

      Growth and agar quality of Gracilaria heteroclada (Zhang et Xia) grown in a filter tank 

      MRJ Luhan, F Harder & AQ Hurtado - Philippine Agricultural Scientist, 2006 - College of Agriculture, University of the Philippines Los Baños
      Gracilaria heteroclada Zhang et Xia was grown in filter tanks to determine the growth, agar quality and uptake pattern of nitrogen and to observe the water quality in recirculating water system with seaweed.

      Rapid uptake of nitrogen in G. heteroclada was observed within the first 24th of culture. Filling up of the nitrogen pools in the cell may have continued until the fifth day, the plants started to increase in weight, proportionate to the uptake rate of nitrogen duing the experiment. G. heteroclada stocked at 1 kg m-2achieved a specific growth rate (SGR) of approximately 10.4% d-1 during 15d of culture, at total ammonia-nitrogen and nitrite-nitrogen levels of 0.03-0.27 mg L-1 and 0.04-0.19mg L-1, respectively, in the filter tank. Approximately 11% of nitrogen in the water was removed by the seaweed.
    • Article

      Impact of AMPEP on the growth and occurrence of epiphytic Neosiphonia infestation on two varieties of commercially cultivated Kappaphycus alvarezii grown at different depths in the Philippines 

      IAG Borlongan, KR Tibubos, DAT Yunque, AQ Hurtado & AT Critchley - Journal of Applied Phycology, 2011 - Springer
      Two varieties of the carrageenophyte Kappaphycus alvarezii (Tungawan, TUNG; and Giant tambalang, GTAM) from Zamboanga Sibugay, Philippines were used to test the efficacy of Acadian Marine Plant Extract Powder (AMPEP) as source of nutrients for growth, and to determine if applications had any effect on the percent occurrence of an epiphytic infestation of the red alga Neosiphonia sp. at four different depths in the sea. Results showed that the use of AMPEP significantly (P < 0.05) increased the growth rate of both Kappaphycus varieties tested but decreased the percent occurrence of Neosiphonia sp. The percent occurrence of Neosiphonia sp. infection (6–50% at all depths) of both Kappaphycus varieties with AMPEP treatment was significantly lower than the controls (i.e., 10–75% at all depths). Both the growth rate of the cultivated seaweed and the percent occurrence of the epiphytes decreased as the cultivation depth increased. Plants dipped in AMPEP and suspended at the surface had the highest growth rates (i.e., 4.1%, TUNG; 3.1%, GTAM) after 45 days; those without AMPEP dipping had the highest percent occurrence of Neosiphonia infection (viz. 70–75%). The occurrence of Neosiphonia infestation was found to be correlated with changes in irradiance and salinity at the depths observed. The results suggested that both varieties of K. alvarezii used in this study have the fastest growth rate when grown immediately at the water surface. However, in order to minimize damage caused by the occurrence of epiphytic Neosiphonia, K. alvarezii should be grown within a depth range of 50–100 cm. These observations are important for the improved management of Kappaphycus for commercial farming. Furthermore, the use of AMPEP treatments for enhancement of growth and reduction deleterious Neosiphonia sp. infections is encouraging.
    • Article

      Optimization of culture conditions for tissue culture production of young plantlets of carrageenophyte Kappaphycus 

      DAT Yunque, KR Tibubos, AQ Hurtado & AT Critchley - Journal of Applied Phycology, 2011 - Springer Verlag
      To improve the production of Kappaphycus plantlets in tissue culture, optimum media concentrations of an Ascophyllum nodosum extract (Acadian Marine Plant Extract Powder, AMPEP), plant growth regulators (PGR), pH–temperature combinations, and explant density were determined. Kappaphycus alvarezii var. tambalang purple (PUR), kapilaran brown (KAP), vanguard brown (VAN), adik-adik (AA), tungawan green (TGR), and K. striatum var. sacol green (GS) were used as explants. Based on the shortest period for shoot emergence and the economical use of AMPEP, the optimum enriched media was 3.0 mg L−1 AMPEP and 0.1 mg L−1 AMPEP + PGR 1 mg L−1 each phenylacetic acid (PAA) and zeatin for PUR, 1.0 mg L−1 AMPEP + PGR for KAP and GS, 0.1 mg L−1 AMPEP + PGR for VAN, and 3.0 mg L−1 AMPEP and 0.001 mg L−1 AMPEP + PGR for AA and TGR. Results showed that the addition of PGR to low concentrations of AMPEP hastened shoot formation. pH–temperature combinations for the most rapid shoot formation were determined for the brown (KAP) and purple (PUR) color morphotypes of K. alvarezii var. tambalang and the green morphotype of K. striatum var. sacol (GS) cultured in 1.0 mg L−1 AMPEP + PGR. The brown morphotype produced the most number of shoots at pH 7.7 at 20°C after as little as 20 days. Purple K. alvarezii showed an increased shoot formation at pH 6.7 at 25°C and the green K. striatum morphotype at pH 8.7 at 25°C. The optimum number of explants added to the culture media was also determined for tungawan green (TGR), brown (KAP), and tambalang purple (PUR) varieties of K. alvarezii in 1.0 mg L−1 AMPEP + PGR. The number of explants and the volume of the culture media combination were also tested. The highest average number of shoots formed occurred in two explants:1 mL culture media (2:1) for KAP and PUR (35.00% and 16.67%, respectively) and 1 explant: 2 mL culture media for the TGR (100.00%) with a range of 0.5–3.0 mm shoot length after 40 days in culture. The earliest shoot formation was observed after 21 days for the brown and 9 days for both the green and purple color morphotypes of Kappaphycus, in all densities investigated. This indicated that within the range tested, the density of explants did not have a significant effect on the rate of shoot formation but did influence the average number generated from the culture. The rate of production of new and improved Kappaphycus explants for a commercial nursery stock was improved through the use of AMPEP with optimized culture media pH, temperature, and density conditions.
    • Article

      Photosynthetic responses of ‘Neosiphonia sp. epiphyte-infected’ and healthy Kappaphycus alvarezii (Rhodophyta) to irradiance, salinity and pH variations 

      IAG Borlongan, MRJ Luhan, PIP Padilla & AQ Hurtado - Journal of Applied Phycology, 2016 - Springer Verlag
      Understanding the physiological condition of seaweeds as influenced by biotic and abiotic stress is vital from the perspective of massive expansion and sustainability of seaweed-based industries. The photosynthetic responses ofNeosiphonia sp. epiphyte-infected (INF) and healthy (HEA) Kappaphycus alvarezii under various combinations of irradiance, salinity and pH were studied using photosynthesis-irradiance (P-E) curves. Measurements of algal photosynthetic rates, expressed in terms of amount of oxygen production per fresh weight biomass per unit time (mg O2 g−1 FW h−1), were carried out using the light-dark bottle technique. Neosiphonia-infected K. alvarezii (INF) had lower photosynthetic rates than healthy ones (HEA). Similarities (p > 0.05) in light-saturated photosynthesis rates (Pmax) and significant differences (p < 0.05) in initial slope of curve (α) between INF and HEAK. alvarezii suggest that both samples are adapted to similar light conditions and differs only on photosynthetic efficiency. Low Pmax (0.7–2.0 mg O2 g−1 FW h−1) and high initial saturation irradiances (Ek = 90–519 μmol photons m−2 s−1) of INF seaweeds resulted to their low photosynthetic efficiency (α = 0.002–0.010). Such decline in α is attributed to the epiphyte, as Neosiphonia sp. covered almost the entire surface of K. alvarezii. An increase in chlorophyll-a (35–42.1 vs. 27.7–31.5 μg g−1 FW, HEA) and phycobilin (1.96–2.39 vs. 1.16–1.58 mg g−1 FW, HEA) contents was also observed in INF samples, suggesting acclimation to low-irradiance conditions, as a result of competition for light between the epiphyte and host. Both INF and HEA K. alvarezii also exhibited broad photosynthetic tolerance to short-term changes in irradiance, with no photoinhibition at the highest irradiance of 850 μmol photons m−2 s−1. K. alvarezii had a euryhaline photosynthetic response, with optimum salinity of 35 psu. Photosynthetic rates increased with decreasing pH, revealing K. alvarezii’s ability to modify its photosynthetic affinity for acidic seawater conditions; yet, their underlying mechanism of response to pH shifts still need to be further examined.
    • Article

      Propagule production of Eucheuma denticulatum (Burman) Collins et Harvey by tissue culture. 

      AQ Hurtado & DP Cheney - Botanica Marina, 2003 - Walter de Gruyter
      Plants of Eucheuma denticulatum collected from Danajon Reef, Bohol, the Philippines were used to produce tissue cultures for the purpose of generating new strains. The plants were sectioned and grown in media encouraging callus growth. New shoots were produced after 3 months of in vitro culture. After another 3 months of laboratory growth, 5 plants were outplanted in the field. After 4 months growth at approximately 0.50 m depth, the five plants grew to biomasses that ranged from 354.9 to 1055.9 g wet weight. They demonstrated growth rates that ranged from 5.8 to 7.2% day−1. The growth rates of the plants produced through tissue culture in this study suggest that such plants can grow at rates as good as, if not better than, those of 'seedlings' produced by the traditional method in the commercial cultivation of E. denticulatum.
    • Conference paper

      Research on molluscs and seaweeds 

      AC Fermin & AQ Hurtado - In LMB Garcia (Ed.), Responsible Aquaculture Development in Southeast Asia. Proceedings of the Seminar-Workshop on Aquaculture Development … Southeast Asia organized by the SEAFDEC Aquaculture Department, 12-14 October 1999, Iloilo City, Philippines, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This paper reviews the progress of mollusc and seaweed research at SEAFDEC AQD from 1995 to 1999. Because of the pressing need for seedstocks for stocking, research on the donkey s ear abalone, Haliotis asinina focused on the development of seed production and culture techniques. To improve the spawning performance and egg/larvae production of captive broodstock studies on reproductive biology, management of broodstock and development of diet were conducted. Studies to refine techniques for post-larval settlement and metamorphosis and development nursery rearing techniques were carried out to increase production of abalone juveniles. An artificial diet has been developed to enhance growth rates of juveniles during nursery as well as grow-out. However, since long-term use of artificial feeds did not favor the growth and survival of abalone during grow-out culture in tanks due to difficulties in maintaining water quality, sequential feeding with artificial diets and then seaweed Gracilariopsis bailinae seemed more practical.

      Broodstock development and seed production were the major research areas for the window-pane oyster Placuna placenta. Gonad development was enhanced by feeding a mixture of high densities of Isochrysis galbana and Tetraselmis tetrahele at a 3:1 ratio. P. placenta larvae reared with Isochrysis as feed showed best growth and survival. Settling stage was reached after 14 days of rearing. A salinity of 34 ppt was optimal for larval survival. Poor growth and survival of larvae was observed at low (10 ppt) and high salinity (40 ppt) levels. Re-stocking immature adults and juveniles was conducted in a depleted coastal bed to evaluate potentials for recruitment of the window-pane oyster. After 91 days, a survival rate of 51% was observed among immature adults. No juveniles survived after re-stocking.

      Studies on seaweeds focused on three economically important genera of red algae: (1) Gracilaria, (2) Gracilariopsis, and (3) Kappaphycus. These studies are in recognition of Gracilaria and Gracilariopsis as agarophytes and Kappaphycus as carrageenophyte having significant roles in the seaweed industry. Research studies therefore aimed to optimize culture techniques for and to develop environment-friendly aquaculture of these seaweeds. Optimization of biomass production was attempted by manipulating the nutrient environment, biomass density, the proportion of harvested biomass, and crop quality for conversion to agar and carrageenan. The use of G. bailinae as a bio-filter focused on the capacity of the seaweed and its agar to sequester heavy metals like cadmium copper, lead and zinc after exposure to various concentrations of these metals. Likewise, excess levels of nitrogen and phosphorus in a finfish broodstock tank with re-circulating water were reduced, demonstrating the efficiency of the seaweed as a bio-filter in aquaculture. Eco-physiological studies of Gracilaria changii, G. coronopifolia, G. firma, and G. bailinae involved the mass production of spores-in vitro as a possible source of seedlings for outplanting. A socioeconomic survey of Kappaphycus culture in the Philippines revealed that, although expensive, deep-sea farming of K. alvarezii using the multiple raft long-line technique was more productive and profitable than the traditional mono-line or the popularly practiced hanging long-line technique.
    • Book chapter

      A review of Kappaphycus farming: prospects and constraints 

      L Hayashi, AQ Hurtado, FE Msuya, G Bleicher-Lhonneur & AT Critchley - In J Seckbach, R Einav & A Israel (Eds.), Seaweeds and their Role in Globally Changing Environments, 2010 - Springer Netherlands
      Series: Cellular Origin, Life in Extreme Habitats and Astrobiology; 15
      A review of Kappaphycus (broadly including Eucheuma) farming is presented, including the current possibilities and challenges with the goal of contributing to sustainable mariculture management practices.
    • Book chapter

      Seagrasses 

      AQ Hurtado - In Training Handbook on Rural Aquaculture, 2009 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      The seasonality and economic feasibility of cultivating Kappaphycus alvarezii in Panagatan Cays, Caluya, Antique, Philippines 

      AQ Hurtado, RF Agbayani, R Sanares & MTR de Castro-Mallare - Aquaculture, 2001 - Elsevier
      Vegetative thalli of brown and green Kappaphycus alvarezii were cultivated in Panagatan Cays, Caluya, Antique, Philippines, over 60- and 90-day periods using hanging-long line (HL), fixed off-bottom (FB), and hanging long line–fixed off-bottom (HL–FB) methods to determine the daily growth rate and yield. A completely randomized design experiment with six replicates of 5-m line cultivation rope was used in the study. An economic analysis was prepared to determine the viability of the culture systems used. To determine the effect of strain, culture technique, culture days and culture month on the daily growth rate and yield, a combination of these different factors was treated as a single treatment. Results show that at 60-day culture period, daily growth rate and yield in all techniques were lowest in July–August and highest in January–February. Higher growth rate (2.3–4.2% day−1) and yield (3.6–15.8 fresh weight kg m−1 line−1) were obtained from September to February. Significant differences (P<0.05) in growth rate and yield were determined between culture months. At 90-day culture period, there were no significant differences in growth rate and yield between culture months; however, a significant difference was found between culture techniques. The average production (dry weight kg crop−1) of K. alvarezii when grown at 60-day culture period during lean and peak months using HL, FB and HL–FB techniques ranged from 421 to 3310 kg with HL–FB the highest and FB the lowest. Net income, return on investment (ROI) and payback period were all positive during peak months, but negative values were obtained during lean months. Only seaweed grown on HL technique during the peak months at 90-day culture period showed positive income, ROI and payback period. The seasonality of cultivating K. alvarezii is shown in this present study. This paper further shows the best culture technique to be adopted at certain months of the year to produce the highest yield and income.
    • magazineArticle

      Seaweed production: Farming Kappaphycus in the Philippines 

      AQ Hurtado - Global Aquaculture Advocate, 2002 - Global Aquaculture Alliance
    • Conference paper

      Seaweed research at SEAFDEC Aquaculture Department 

      AQ Hurtado - In AQ Hurtado & MRJ Luhan (Eds.), Proceedings of the National Seaweed Symposium, September 3-4, 2002, Cebu City, 2003 - Seaweed Industry Association of the Philippines
      Seaweed research at the Aquaculture Department of SEAFDEC focuses mainly on 2 genera of agarophytes (Gracilaria and Gracilariopsis) and carrageenophytes (Eucheuma and Kappaphycus).

      From 1988 to 1998, research works were mainly on Gracilaria and Gracilariopsis along these areas: (1) refinement of culture technique, (2) basic biology, production ecology, and corp management, (3) product utilization, (4) screening and characterization of natural products, and (5) economics of farming system.

      Four years ago, the Seaweed Program of the Department re-focused its thrust on Advanced Aquaculture Technologies (Biotechnology) to include also Eucheuma and Kappaphycus in answer to the needs of the industry.

      This paper briefly describes the highlights of the different studies done on biotechnology.
    • Book

      Seaweeds of Panay 

      AQ Hurtado, MRJ Luhan & NG Guanzon Jr. - 2006 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This practical book on the seaweeds of Panay, Philippines, acquaints and provides information to members of the academe and research institutions, policy makers, fishermen and businessmen regarding the taxonomy, distribution, ecology and economic importance of these resources. It consists of 4 major parts: (1) Introduction, which reviews the literature, habitat, distribution, morphological structure and reproduction; 2) Classification, which describes the classes to which the seaweeds generally belong; 3) Collection and preservation, which explains the procedure used in treatment of specimens; and, 4) Taxonomic list. A glossary is included, covering technical terms used. All species listed and described in this book are macrobenthic and were collected in Panay and Guimaras Islands.
    • Article

      Use of Acadian marine plant extract powder from Ascophyllum nodosum in tissue culture of Kappaphycus varieties 

      AQ Hurtado, DA Yunque, K Tibubos & AT Critchley - Journal of Applied Phycology, 2009 - Springer Verlag
      Three varieties of Kappaphycus alvarezii (Kapilaran, KAP), Tambalang purple (PUR), Adik-adik (AA), and one variety of Kappaphycus striatum var. sacol (green sacol (GS) were used to determine the efficiency of Acadian marine plant extract powder (AMPEP) as a culture medium at different concentrations, for the regeneration of young plants of Kappaphycus varieties, using tissue culture techniques for the production of seed stock for nursery and outplanting purposes for the commercial cultivation of carrageenophytes. A shorter duration for shoot formation was observed when the explant was treated with AMPEP + Plant Growth Regulator (PGR = PAA + zeatin at 1 mg L−1) compared to AMPEP when used singly. However, four explants responded differently to the number of days required for shoot formation. The KAP variety took 46 days to form shoots at 3–4 mg L−1 AMPEP + PGR; while PUR required 21 days at 3–5 mg L−1 AMPEP and 3–4 mg L−1 AMPEP + PGR. AA required 17 days at 3–5 mg L−1 AMPEP and AMPEP + PGR; and GS 25 days at 1 mg L−1 AMPEP + PGR. It was observed that among the four explants used, PUR and AA initiated shoot formation with the use of AMPEP only at higher concentrations (3–5 mg L−1) after a shorter period. Only PUR responded positively to ESS/2 for shoot initiation. The use of AMPEP alone and/or in combination with PGR as a culture medium in the propagation of microplantlets using tissue culture technique is highly encouraging.