Now showing items 1-15 of 15

    • Conference paper

      Cage culture of Kappaphycus alvarezii (doty) doty and Epinephelus sp. 

      AQ Hurtado-Ponce - In PM Aliño (Ed.), Proceedings of the Second National Symposium in Marine Science, 5-7 November 1992, Mindanao State University, Tawi-tawi, Philippines, 1994 - University of the Philippines, Marine Science Institute
      Kappaphycus alvarezii seedlings were cultured in cluster, vertically and horizontally using nylon monofilament rope attached to a bamboo raft installed inside a 5 x 5 m floating cage. Juveniles of Epinephelus sp. were stocked as biological control to grazers.

      Specific growth rate (% increase in weight day-1) and production (g m-1 line-1) of Kappaphycus were determined every 45 days and production of Epinephelus was determined after 120 days. Specific growth rate of Kappaphycus alvarezii was significantly affected by the culture technique used. An average specific growth rate of 3.7 %, 3.8 % and 5.3 % was recorded when K alvarezii was cultured in clusters, vertically and horizontally in that order. Horizontal technique of culturing K alvarezii was significantly different from vertical and cluster techniques (DMRT = 0.05). Production (g m-1 line-1) of K. alvarezii ranged from 766 to 1,970, (in clusters), 1,110 to 1975 (vertically) and 1,204 to 1,533 (horizontally). These values were significantly affected by the culture month but insignificantly affected by culture technique (DMRT = 0.05). After 120 days of culture, mean weight of Epinephelus sp. was 297 g; % weight gain cage-1 was 233; survival rate = 68 %; fish production = 5 kg; and FCR = 6.
    • 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

      Carpospore germination and early stages of development in Gracilaria edulis (Gmelin) Silva and Gracilaria rubra Chang et Xia (Gracilariales, Rhodophyta) 

      AQ Hurtado-Ponce - The Philippine Scientist, 1993 - San Carlos Publications, University of San Carlos
      Carpospore germination and early stages of development in Gracilaria edulis and Gracilaria rubra of the Philippines are described for the first time. Both species follow the "Dumontia type" or the immediate discal type of growth. Young plants with secondary branches were observed after 17 days of germination.
    • 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

      Effect of stocking density and nutrients on the growth and agar gel of Gracilariopsis bailinae (Gracilariales, Rhodophyta) 

      EAJ Chavoso & AQ Hurtado-Ponce - The Philippine Scientist, 1995 - San Carlos Publications, University of San Carlos
      The effect of additional nutrients and varying stocking densities (500, 1000, and 2000 g m-2) on the growth and physical properties of Gracilariopsis bailinae was determined. Growth was significantly higher (L = 0.05) at a stocking density of 500g both in enriched (3.5%/day) and unenriched (1.9%/day) treatment, but growth was not significantly different between 1000 and 2000g density. A decreasing growth rate was observed with increasing stocking density. Significant differences in gel strength and gelling temperatures were observed only at 2000 g m-2 both in enriched and unenriched treatment. Results of the study showed that additional nutrients are necessary for the growth of G. bailinae and its agar quality.
    • Article

      The genus Gracilariopsis (Rhodophyta, Gracilariales) in the Philippines: morphological and taxonomic confirmations 

      AQ Hurtado-Ponce & LM Liao - The Philippine Scientist, 1998 - University of San Carlos
      Reports of the economically-important agarophytic seaweed genus Gracilariopsis Dawson from Philippine waters are verified for the first time. Cystocarpic, spermatangial and tetrasporic materials collected from various localities in eastern Panay and northwestern Negros islands conform to the circumscription of this recently reinstated genus. Materials are referred to Gracilariopsis heteroclada Zhang & Xia after morphological comparisons with type materials from southern China. In addition, a discussion of the complicated nomenclatural history of this species is included.

      Another putative Gracilariopsis species is reported from Zamboanga City based on cystocarpic materials alone. This species differs from G. heteroclada with its smaller gonimoblast cells and larger height:width ratio of the gonimoblast mass. Vegetatively, the thallus is smooth, devoid of fine, determinate branchlets observed in G. heteroclada.
    • Article

      Gracilaria (Rhodophyta) farming in Panay, Western Visayas, Philippines 

      AQ Hurtado-Ponce, GPB Samonte, MRJ Luhan & NG Guanzon Jr. - Aquaculture, 1992 - Elsevier
      Interviews were conducted among eight Gracilaria growers in Panay, Western Visayas, Philippines from March to July (1990) using a structured questionnaire. The "rice planting" method was employed by farmers growing seaweeds in natural drainage canals and ponds. Initial harvests are made 15–60 days after planting. Higher production [ 7–14 t (dry) ha−1 year−1] are obtained from cultures in canals than in ponds [3–4 t (dry) ha−1 year−1]. The net income derived from culture in ponds is estimated at P698/crop or P6313/year (US$234/year). A higher net income of P4936/crop or P41766/year (US$1547/year) was generated from Gracilaria farming in canals. Returns on investment (ROI) from farming in ponds and canals are 39% and 908%, respectively. Payback period is 2 months in canal farming and 1.8 years in pond farming.
    • Conference paper

      Gracilaria studies at SEAFDEC/AQD 

      AQ Hurtado-Ponce - In Report on a Regional Study and Workshop on the Taxonomy, Ecology and Processing of Economically Important Red Seaweeds, 24-27 January 1995, Bangkok, Thailand, 1996 - Network of Aquaculture Centres in Asia-Pacific
      Series: NACA Environment and Aquaculture Development Series No. 3
      Research in seaweed from 1988–1994 focused on the agar producing Gracilaria. Studies in the following areas were also conducted: inventory of the seaweed resources; production ecology; farming systems; and agar characterisation. Six species of Gracilaria and one Gracilariopsis abound in the Western Visayas. There were monthly variations in biomass and agar quality of G. blodgettii, G. manilaensis and G. heteroclada collected at different places.

      The bulk of the studies were carried out on Gracilariopsis heteroclada because of its wide distribution, fast growth characteristics and good quality agar. Its reproductive state was seasonal with tetrasporophyte abundant in May and carposporophyte in January. Seventy-five percent harvesting of the available biomass was sufficient for the next cropping season. Harvesting the seaweed using “araña” was not appropriate in places where the biomass was exposed to air during the lowest tide. The addition of nutrients to the stock increased the growth rate of the seaweed and gel strength of the agar. G. heteroclada grown at lower stocking density in hapa nets, both in floating cages and in ponds, gave higher growth rates and production than at higher stocking densities. This species, when polycultured with P. monodon at lower stocking density combinations, gave the highest growth rate and income. Likewise, this species when cultured vertically in ropes inside a floating cage showed encouraging results. G. heteroclada, when grown at 24–25 ppt under tank conditions, produced the highest gel strength.
    • Conference paper

      Growth rate of Gracilariopsis heteroclada (Rhang et Xia) Zhang et Xia (Rhodophyta) in floating cages as influenced by Lates calcarifer Bloch 

      AQ Hurtado-Ponce - In HP Calumpong & EG Meñez (Eds.), Proceedings of the 2nd RP-USA Phycology Symposium/Workshop, Supplement, 6-10 January 1992, Cebu City, Philippines, 11-18 January 1992, Dumaguete City, Philippines, 1994 - Philippine Council for Aquatic and Marine Research and Development
      Fragments of Gracilariopsis heteroclada weighing 10 g each were inserted in a polypropylene rope, suspended at different depths (25 cm, 50 cm and 100 cm below the water surface) and cultured with Lates calcarifer fingerlings (22-25 cm long and 158-252 g) in floating net cages from April to October. After seven months of culture, the specific growth rate of G. heteroclada was found to be influenced significantly (p ≤ 0.05) by the interaction of three factors: sea bass, water depth, and month of culture.

      Highest growth rate of Gracilariopsis heteroclada was recorded at 25 cm below the water surface during the month of April unaffected by the presence or absence of sea bass; while the lowest growth rale was observed at 100 cm during the months of September and October in the absence of sea bass. Approximately, 172 (dry) g m-2 mo-1 is produced from this culture system.

      The average length and weight of Lates calcarifer at the end of seven-month culture period was 35-39 cm and 565-741 g, respectively. Percentage weight gain/cage was 195-258, survival rate was 92-100%, and total fish production per cage was 6,780-9,637 g.
    • Article

      Influence of extraction time on the rheological properties of agar from some Gracilaria species from the Philippines 

      AQ Hurtado-Ponce - Botanica Marina, 1992 - Walter de Gruyter
      The influence of extraction time on the clean anhydrous yield, rheological properties, dynamic gelling and melting temperatures of 1.5% agar from six species of Gracilaria and one species of Gracilariopsis collected from the Philippines was determined. The lowest agar yield was measured from Gracilaria 'verrucosa' (10.1%) even after 120 minutes extraction while the highest yields were recorded from G. coronopifolia both after 30 (23.5%) and 60-minute extraction times (26.1%) and G. eucheumoides after 120-minute extraction time (27.3%). A 60-minute extraction of G. heteroclada produced gels with the highest breaking strength (1013 g), the maximum cohesiveness (7.4 mm), the greatest breaking energy (7481 g mm), and the greatest stiffness (137.3 g/mm -1). Gracilaria blodgettii gave the weakest gel tested. Dynamic gelling temperature was lowest for G. blodgettii at 60 min (28 °C) and highest for G. edulis at 120 minutes of extraction (46.3 °C). Melting temperature was lowest at 30 min extraction for G. salicornia (58.0 °C) and highest at 30 minutes for G. edulis (95.0 °C).

      A strong interactive effect of species, extraction time, and rheological properties was observed, but there was no interaction observed among the species, extraction time and temperatures. Each species showed good rheological properties at a specific extraction time.
    • Article

      New records of a marine macrobenthic algae of Panay and Guimaras Islands 

      MRJ Luhan, AQ Hurtado-Ponce, NC Guanzon & GC Trono - Philippine Journal of Science, 1992 - Science and Technology Information Institute
      Thirty new records of macrobenthic algae for Panay and Guimaras Islands are reported, consisting of 12 species of Chlorophyceae, 4 Phaeophyceae and 14 Rhodophyceae.
    • Conference paper

      Research on seaweeds and mollusks 

      AQ Hurtado-Ponce - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Research on seaweeds focused on the carrageenan-producing Kappaphycus alvarezii and the agar-producing Gracilaria spp. Growth of K. alvarezii was better on horizontal lines than on vertical or cluster lines from bamboo rafts. All morphotypes (brown green, and red) grew faster at 50 cm than at 100 cm below the water surface, but the green morphotype showed better carrageenan properties. A socioeconomic survey of K. alvarezii farming in Panagatan Cays, Antique revealed that a farmer has an average annual production of 3 tons/ha (dry) with the fixed bottom and hanging longline methods.

      Three species of Gracilaria in natural beds in lloilo showed monthly variations in biomass and agar quality; G. heteroclada had the highest biomass and gel strength. When this species was grown in tanks, growth and agar sulfate content were influenced by the interaction of light, salinity, and nutrients. Enriched and unenriched stocks of G. heteroclada differed in agar quality. When G. heteroclada was grown with the tiger shrimp Penaeus monodon in extensive ponds, the highest growth rate and production were obtained at the seaweed stocking density of 250 g/m2; this was in November when average water temperature, transparency, and salinity were low. Salinity tolerance varies among Gracilaria species.Oyster (Crassostrea iredalei) and mussel (Perna viridis) farming in Western Visayas were assessed in 1992 in terms of the culture methods, socioeconomics, marketing, and profitability. A more localized survey of oyster and mussel fanning was conducted through rapid rural appraisal in two coastal towns in 1993. A farmer-participatory study followed in 1994 for the culture of oysters, mussels, seaweeds, and rabbitfishes in a river mouth in Dumangas, lloilo. Green mussel, brown mussel (Modiolus metcalfei), and seaweeds transplanted to Dumangas from Capiz have reproduced. In another study, the green mussel was tested as a biological filter in tiger shrimp ponds; shrimps stocked with mussels grew better than those without.

      A nationwide survey on the Placuna placenta fishery in 1993 showed 27 remaining 'kapis' beds; many others have been depleted due to excessive gathering, pollution, siltation, and trawling. Broodstocks are being developed to produce 'kapis' seed for grow-out and restocking. For the first time at AQD, adult donkey-ear abalone Haliotis asinina from the wild spawned naturally in laboratory tanks.

      Juvenile abalones can be successfully grown on Gracilaria or abalone diet.
    • Conference paper

      Seaweed: Gracilaria 

      AQ Hurtado-Ponce - In F Lacanilao, RM Coloso & GF Quinitio (Eds.), Seminar-Workshop on Aquaculture Development in Southeast Asia and Prospects for Seafarming and Searanching; 19-23 August 1991; Iloilo City, Philippines., 1994 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This paper reviews the studies on Gracilaria/Gracilariopsis conducted from 1988 to 1991 by the Aquaculture Department, Southeast Asian Fisheries Development Center. It includes 114 species of macrobenthic algae collected in Panay, the nomenclature of Gracilariopsis heteroclada previously described as Gracilaria sp., and the biology, ecology, and farming systems of Gracilariopsis. Agar quality of the different species of Gracilaria and the effect of seasonal variation on the quality and quantity of agar produced from Gracilariopsis heteroclada were also studied.
    • Book

      Seaweeds of Panay 

      AQ Hurtado-Ponce, MR Luhan & NG Guanzon Jr. - 1992 - 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

      Vertical rope cultivation of Gracilaria (Rhodophyta) using vegetative fragments 

      AQ Hurtado-Ponce - Botanica Marina, 1990 - Walter de Gruyter
      Preliminary field culture of Gracilaria using vegetative fragments inserted between braids of ropes suspended vertically inside a floating cage was undertaken to assess the daily growth rate and monthly yield as influenced by three different spacing intervals.

      Daily growth rate of cuttings at 10 cm intervals ranged from 0.6 to 7.2% with yields of 11 to 415 g m-1 line1, those at 15 cm from 1.4 to 9.1% with yields of 18 to 502 g m-1 line-1, and at 20 cm from 1.7 to 10.5% and with yields of 20 to 379 g m-1 line-1. Both growth and yield were minimum in December at all spacing intervals but maximum in April at 10 and 15 cm and in February at 20 cm.

      Results of the analysis of variance (ANOVA) showed a non-significant interaction between spacing interval and culture month on daily yield of Gracilaria. This indicates that the effect of spacing interval on the daily growth rate and monthly yield was not significantly influenced by the culture month; likewise the effect of culture month did not differ significantly with the intervals used. The main effects, however, of spacing interval and culture month to daily growth rate were significant. Yield was significantly affected by the culture month but not by spacing interval.