Now showing items 1-20 of 21

    • Article

      Cage culture of Kappaphycus alvarezii var. tambalang (Gigartinales, Rhodophyceae) 

      AQ Hurtado-Ponce - Journal of Applied Phycology, 1992 - Springer Verlag
      Kappaphycus alvarezii var. tambalang was cultured in a 3 × 3 m bamboo raft installed inside a 4 × 4 m floating net cage of Lates calcarifer (sea bass) broodstock at SEAFDEC Sub-station Igang, Guimaras, Philippines, from December 1989 to May 1990. Growth and production of K. alvarezii var. tambalang was influenced by the culture months. The highest growth rate and production were recorded in January and May, respectively, while the lowest growth rate and production were observed in March. Average growth rate (wet weight) ranged from 3.72 to 7.17% day-1, while production ranged from 575.5 to 2377 g m-1 line-1. A total production of approximately 123 t (fresh) or 37 t (dried) ha-1 in the 5-month harvest season was produced from this culture system. Cultivation ofK. alvarezii var. tambalang in cages is possible, which indicates that seaweeds can be grown with carnivorous finfish, a practice which is still untapped.
    • Article

      Carrageenan properties and proximate composition of three morphotypes of Kappaphycus alvarezii Doty (Gigartinales, Rhodophyta) grown at two depths 

      AQ Hurtado-Ponce - Botanica Marina, 1995 - Walter de Gruyter
      Three morphotypes (brown, green and red) of Kappaphycus alvarezii grown at two depths were evaluated for carrageenan properties and proximate composition. The green morphotype was significantly different from the brown and red in all carrageenan properties except for sulfate content at 50 cm below the water surface; and significantly different only from the brown at 100 cm. Except for ash content and nitrogen free extract there were no significant differences in proximate composition (nitrogen, crude protein, crude fat, crude fiber) among the three morphotypes.
    • Conference paper

      Development of integrated multi-trophic aquaculture using sea cucumber 

      S Watanabe, M Kodama, JG Sumbing & MJH Lebata-Ramos - In K Gruenthal, M Rust, P Olin & E Trentacoste (Eds.), Genetics in Aquaculture: Proceedings of the 42nd U.S.-Japan Aquaculture Panel Symposium, La Jolla, CA, October 1, 2014, 2017 - United States Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service
      Series: NOAA technical memorandum; NMFS-F/SPO-168
      In Southeast Asian countries, aquaculture production continues to increase. Environmental deterioration associated with water and sediment eutrophication by aquaculture effluent has been problematic, sometimes resulting in disease outbreaks and fish kills due to hypoxia and hydrogen sulfide poisoning. Integrated multi-trophic aquaculture (IMTA) is one of the promising measures for sustainable aquaculture. In this study, a box model estimation of nitrogen (N) budget based on experimental data and values from literature was made for a system of sandfish (Holothuria scabra) in sea cage IMTA with milkfish (Chanos chanos) and Elkhorn sea moss (Kappaphycus alvarezii).

      Information on stocking density, stocking size, mortality, growth, feed ration, feed assimilation, NH4-N production and NH4-N absorption of these species was obtained from a series of experiments and existing literature. In the production system 26 g milkfish were cultured in a 5 x 5 x 4 m cage at the stocking density of 36.7 ind/m3 with the initial feeding ration of 10% of body weight which was gradually decreased to 4% over time; 10 g sandfish were cultured in a cage with the same bottom area as milkfish cage hanged under the milkfish cage to trap particulate N waste (i.e. feces and leftover feed) at the stocking density of 35 ind/m2; the stocking weight of Elkhorn sea moss line culture was 10 kg; culturing period was 200 days.

      It was estimated that milkfish culture cumulatively produced 145 kg of particulate N, and milkfish and sandfish together produced 60 kg of NH4-N in 200 days of culture. Daily assimilation rate of the particulate N by sandfish ranged 3.4 - 12.4%, and 4.3% of the particulate N was estimated to be removed by sandfish in 200 days of culture. Daily absorption rate of NH4-N by Elkhorn sea moss increased exponentially with time and reached 100% after 125 days of culture. Cumulative NH4-N was estimated to be depleted after 162 days of culture. For complete utilization of particulate N by the end of culture, sandfish stocking density should be 805 ind/m2, which is 200 times as high as that in existing sandfish aquaculture operations.
    • Conference paper

      Developments in seaweed farming in Southeast Asia 

      RS Simbajon & MA Ricohermoso - 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
      During the last thirty years, seaweed farming has progressed in the region comprising the Association of Southeast Asian Nations (ASEAN). Farm production reached a high of 146,500 mt of dried seaweeds in 1997 from an initial harvest of 500 mt in 1973. In 1997, the ASEAN region produced about 90% of the world s production of carrageenophyte seaweed, providing raw materials for the US$35O million world carrageenan market. Two species of carrageenophytes, Kappaphycus alvarezii (=Eucheuma cottonii) and Eucheuma denticulatum (=Eucheuma spinosum), constitute the base of the seaweed industry in the region. K. alvarezii is predominantly farmed in the Philippines and Malaysia while E. denticulatum is dominant in Indonesia. Vegetative propagation is still applied in all farmed species of carrageenophytes, while the monoline method remains the most popular method of farming. Non-traditional farming areas have been established in central and northern Philippines and in Sabah, Malaysia. The culture technology has been developed for Gracilaria sp.; however, no up-to-date reports on production are available. Seaweed farming has become one of the most important sources of livelihood for at least 100,000 coastal families in Southeast Asia, contributing apparently to the reduction of blast and cyanide fishing and to the relative improvement of peace and order in seaweed farming areas.
    • Article

      Distribution and symptoms of epiphyte infection in major carrageenophyte-producing farms 

      CS Vairappan, CS Chung, AQ Hurtado, FE Soya, GB Lhonneur & A Critchley - Journal of Applied Phycology, 2008 - Springer Verlag
      High density commercial farming of carrageenophyte Kappaphycus alvarezii is often plagued with “ice-ice” disease and epiphyte infection, which eventually leads to reduced production and in some cases collapse of crop. Epiphyte outbreak has been occurring regularly in major carrageenophyte farms in the Philippines, Indonesia, Malaysia and Tanzania. Infected materials from these countries were studied to establish baseline information on the epiphyte’s identity, density, symptoms and secondary infection on the host seaweed. The causative organism was identified as Neosiphonia apiculata (Hollenberg) Masuda et Kogame, based on its morphological features. Epiphyte density on host seaweed materials decreased in the following order: the Philippines (88.5 epi cm-2), Tanzania (69.0 epi cm-2), Indonesia (56.5 epi cm-2) and Malaysia (42.0 epi cm-2). Initial symptoms were the presence of tiny black spots, indicating the embedded tetrasporeling in seaweed cortex layer. Vegetative form emerged after 2 weeks measuring less than 0.5 mm in length with a density of less than 25.0 epi cm-2. Upon maturation, infected seaweed takes on a “hairy” appearance with “goose-bumps” like cortical swellings. The epiphyte appears as a solitary plant with multiple secondary rhizoids or as multiple epiphytes appearing from a single cortical opening. At the end of infection, the epiphytes left dark pits on the cortical swelling, and the carrageenophytes are infected by opportunistic bacteria. Bacterial enumeration of healthy and infected seaweed materials showed an increase of more than 300% in total bacterial count on infected materials dominated by Alteromonas sp., Flavobacterium sp. and Vibrio sp.
    • Article

      Economic analysis of bottom line and raft monoline culture of Kappaphycus alvarezii var. tambalang in Western Visayas, Philippines 

      GPB Samonte, AQ Hurtado-Ponce & RD Caturao - Aquaculture, 1993 - Elsevier
      A survey was conducted among 72 seaweed (Kappaphycus sp.) farmers in the Western Visayas region, Philippines, from March to July 1990 to assess their culture practices in terms of production and economic efficiency. Yields of 5.8 tons/ha per crop (dry weight) and 7.6 tons/ha per crop (dry weight) were obtained from bottom line and raft monoline methods, respectively. Investment requirement was P27361/ha for bottom line culture, and P56757/ha for raft monoline culture (P25=US$1). The bottom line method was more profitable with net farm income of P33286/ha per crop compared with P26365/ha per crop for the raft monoline method. The bottom line method of culturing seaweed is more cost-efficient compared with the raft monoline method. Production cost averaged P3.32/kg for the former method, and P5.55/kg for the latter method. Return on investment was also higher at 243% for the bottom line method and 93% for raft monoline.
    • 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.
    • 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 rate of the Philippine abalone, Haliotis asinina fed an artificial diet and macroalgae 

      EC Capinpin Jr. & KG Corre - Aquaculture, 1996 - Elsevier
      The growth rate of Haliotis asinina fed three diets was evaluated over a 120 day period. Juveniles fed the red alga Gracilariopsis heteroclada and an artificial diet grew faster in terms of both total body weight and shell length than those fed the red alga Kappaphycus alvarezii. Juveniles fed the artificial diet produced more weight than those fed G. heteroclada for the first 90 days, but abalone fed G. heteroclada grew faster from Day 105 onwards. In terms of shell length, the artificial diet produced faster growth rates than G. heteroclada for the first 75 days but from Day 90 onwards, faster growth rates were observed in juveniles fed G. heteroclada. Reductions in daily growth rates of juveniles during the latter phase of the growth trial were attributed to channelling of energy into gonad development. G. heteroclada promoted high growth rates over a long-term period (360 days) and is considered to be best suited for abalone farming in the Philippines.
    • 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.
    • Book chapter

      Micro-propagation of Kappaphycus and Eucheuma: Trends and prospects 

      CRK Reddy, NS Yokoya, WTL Yong, MRJ Luhan & AQ Hurtado - In AQ Hurtado, AT Critchley & IC Neish (Eds.), Tropical Seaweed Farming Trends, Problems and Opportunities, 2017 - Springer International Publishing
      Among the red algae, Kappaphycus and Eucheuma are the two most commercially important carrageenophytes farmed extensively in Southeast Asian countries; they rank top in production in terms of volume of raw material produced. The farming of carrageenophytes has emerged as a successful enterprise and provides a promising, alternative livelihood option for low-income, coastal communities in a number of countries. In 2014, carrageenophyte production worldwide, surpassed other red seaweeds and was placed at the top of the production rankings with 10.99 million MT wet weight (77% of total production of farmed red seaweed) and Indonesia being a major producer. However, over time, the productivity of the crop (carrageenophytes) has declined in some regions due to sourcing of seedlings from single, selected genetic stocks considered to have higher yield potential which resulted in strain fatigue, or loss of vigour. The incidences of disease and epiphytic infestations are on rise in recent times which have severely affected biomass production, as well as the yield and product quality (carrageenan). In order to circumvent the crop productivity issues arising from clonal propagation, the raising of planting materials from spores, derived through the red algal sexual reproductive cycle, has been initiated to support the sustainability of selected, farmed carrageenophytes. Alternatively, in vitro tissue culture techniques have also been explored to not only rejuvenate the vigour of seedlings (i.e. the out-planting material) but also to seek seedlings resilient to stress, disease and epiphytes to act as an invigorated mother stock. These efforts have succeeded to a great extent in the development of appropriate techniques for explant culture, callus induction, callus sub-culture and regeneration to micro-propagules with improved traits. The present chapter briefly summarizes the developments and success achieved in micro-propagation of Kappaphycus and Eucheuma and also provides pointers to both gaps and priority areas for future research required for the advancement of sustainable farming of these carrageenophytes.
    • 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.
    • magazineArticle

      The Philippine seaweed industry 

      A Hurtado-Ponce - SEAFDEC Asian Aquaculture, 1998 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A brief outline is given of the Philippine seaweed industry, which involves mainly the red seaweed Kappaphycus alvarezii, produced as a source of the semi-refined or Philippine natural grade (PNG) carrageenan. Other species cultured and marketed include: Gracilaria changii, G.firma, G.heteroclada, G.manilaensis and G.tenuistipitata. The Philippines has the largest carrageenan refinery in Asia. However, production of seaweeds is rather eratic, which is attributed to the following factors: 1) indiscriminate harvesting, seasonal abundance of different species in different areas and lack of proper management; 2) shortage and deteriorating quality of seedlings, especially for Kappaphycus; and 3) natural calamaties.
    • 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

      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

      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.
    • 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.