National Committee on Marine Sciences (NCMS)
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- Laboratory and field growth studies of commercial strains of Eucheuma denticulatum and Kappaphycus alvarezii in the PhilippinesDawes, Clinton J.; Lluisma, A. O.; Trono, G. C. (Springer, 1994-02)Daily growth rates of 0.1 to 8.4% d-1 for the brown form and 0.2 to 6.3% d-1 of the green form were measured for 3 to 5-cm long branches of the tropical red seaweed Kappaphycus alvarezii cultured in the laboratory. Highest growth rates were found using inexpensive enrichments such as soil water and coconut water supplemented with 0.7 mM N and 13 µM P and with a liquid fertilizer, Algafer, produced from seaweeds in the Philippines. Laboratory grown branches of both K. alvarezii and Eucheuma denticulatum transplanted to rafts in the field showed daily growth rates of 4.4 to 8.9% d-1, as high or higher than other reported growth rates. The studies, carried out in the Philippines, demonstrate the viability and high yield of laboratory cultivars and methods to keep laboratory culture costs low.
- Differences in biomass production and carrageenan yields among four strains of farmed carrageenophytes in Northern Bohol, PhilippinesTrono, Gavino C.; Lluisma, Arturo O. (Springer, 1992-11)Comparative studies on the biomass and carrageenan production of two strains of Eucheuma denticulatum and two strains of Kappaphycus alvarezii were made to assess the seasonality in their production capacities. The high and similar refined carrageenan (RC) yields (43–53% of dry wt.) of the four strains in the first cropping season (June–October) coincided with their high biomass production with plants averaging from 1.1 to 1.8 kg each at harvest. The poor RC yields (21–33%) recorded in the second cropping (October–February) coincided with their season of low biomass (av. wt: 0.34 to 1.0 kg). The four strains, however, recorded contrasting performance in the third cropping season (February–July) with the two E. denticulatum strains recording high RC yields (43 and 42.5%) together with high biomass (av. wt: 1.5 and 1.6 kg) in contrast to the low RC yields (30 and 39%) and low biomass (av. wt. 0.21 and 0.28 kg) of the two K. alvarezii strains. Records for semi-refined carrageenan (SRC) yields in the second and third cropping seasons were quite consistent and similar for the four strains (42–55%), except in the second cropping where the two K. alvarezii strains recorded low SRC. These differences in production potentials highlight the need for cropping management of the four strains to improve their cropping performance.
- Clonal propagation of Eucheuma denticulatum and Kappaphycus alvarezii for Philippine seaweed farmsDawes, C. J.; Trono, G. C.; Lluisma, A. O. (Springer, 1993-06)Technique improvement and cost reduction of branch culture, micropropagation, and callus production of carrageenan-yielding seaweeds Kappaphycus alvarezii and Eucheuma denticulatum is presented. Low cost branch culture is possible by enriching seawater with 0.1% coconut water with 1 mg l−1 indole-3-butyric acid for 24 h wk−1 or continuous culture with 0.01% Algafer, a Philippine fertilizer. Micropropagation of 0.5 cm explants had almost 100% new branch production demonstrating the viability of callus regenerated plants. The use of carrageenan as a media for callus production was not effective when compared to agar. Propagules of both species, transferred from the University of the Philippine Marine Science Institute (UPMSI) culture facility to the field, showed daily percent growth rates of 5 to 5.5% d−1 over 84 days. Based on the costs of the UPMSI laboratory, a culture facility in the seaweed farming area is estimated to cost about U. S. $22000 during the initial year and 58% less the second year.
- The farmed Eucheuma species (Gigartinales, Rhodophyta) in Danajon Reef, Philippines: Carrageenan propertiesAzanza-Corrales, R.; Sa-a, P. (Springer, 1990-09)Six cultured ‘strains’ of Eucheuma denticulatum and E. alvarezii, from which stocks can be selected for the development of a Eucheuma ‘seedling bank’, were tested for their carrageenan quality from June to November 1988. Percent yield of all the varieties taken together was apparently higher in June, becoming lower in November (regression, r −0.785, probability, p ⩽ 0.001). Stepwise regression analysis was done to determine the existence of any relationship between any of the following parameters: gel strength, viscosity, sulfate content, month of sampling, and yield, whether taken individually or in combination. Results show variations of the yield with the month of sampling. ANOVA was performed to test whether there are differences in sulfate levels, gel strength, and viscosity between the Eucheuma alvarezii morphotypes. There was no significant difference between the green and the brown types.
- Reproduction in Eucheuma denticulatum (Burman) Collins and Hervey and Kappaphycus alvarezii (Doty) Doty farmed in Danajon Reef, PhilippinesAzanza-Corrales, Rhodora; Mamauag, Samuel S.; Alfiler, E.; Orolfo, M. J. (Elsevier, 1992-04)Occurrence of reproductive structures in seven forms belonging to two species of carrageenophytes, Eucheuma denticulatum and Kappaphycus alvarezii was determined at a farming site at Danajon Reef, Northern Bohol, Philippines during 1987 and 1988. Reproductive plants of these forms were encountered throughout the study period although not all three structures (asexual or tetrasporic form and sexual male and female forms) were represented in each form. For K. alvarezii forms, taking the ‘browns’ (EAB1 and EAB2) and the ‘greens’ (EAG1 and EAG2) collectively, male and female reproductive structures were found throughout the year but no tetrasporic thalli were encountered. Only male and tetrasporic structures were observed for E. denticulatum (EDB and EDG) while the ‘sacul type’ ( EAG3 ) had both structures present throughout the study period. Analysis of variance revealed significant difference (P < 0.05) in the frequencies of reproductive structures of each form.
- The farmed Euchema species in Danajon Reef, Philippines: Vegetative and reproductive structuresAzanza-Corrales, R. (Springer, 1990-03)As part of the information needed for applied research on hybridization of these economically important species, the vegetative and reproductive structures of Eucheuma denticulatum (Burman) Collins and Hervey, and Eucheuma alvarezii Doty being farmed in Danajon Reef, were studied. All cultured ‘strains’ suspected to have developed from original stocks apparently introduced into the area about twelve years ago were sampled monthly from February 1987 to November 1988. Analyses of fresh free-hand and plastic embedded sections revealed the sexual (male, female) and asexual (tetrasporic) structures in E. alvarezii var.tambalang Doty and the absence of the female in E. denticulatum, indicating the suitability of the former species for future manipulative experiments.