Temporal Variation in the Biomass, Quantity and Quality of Agar from Gelidiella acerosa (Forsskål) Feldmann et Hamel (Rhodophyta: Gelidiales) from Cape Bolinao, NW Philippines

Roleda, Michael Y.; Ganzon-Fortes, Edna T.; Montaño, N. E.; Reyes, Flavio

doi:10.1515/botm.1997.40.1-6.487

Cited by 12 publications

(16 citation statements)

References 18 publications

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“…Considering further that the agar content is 35% (though it may vary considerably; Craigie and Leigh 1978, Kapraun et al 1994, Roleda et al 1997, Villanueva et al 1999, the same conserva-500 R.N. Rollon et al tive estimate of annual production may translate to 8.1 t y -1 of agar.…”

Section: Resultsmentioning

confidence: 98%

“…For the cover-biomass exercises, we gathered data within the period July-September 2001. The biomass and growth during this period tend to be high (e.g., Umamaheswara Rao 1973, Abanil et al 1984, Roleda et al 1997, although no clear seasonality has been established (see also the review by GanzonFortes 1994). For the subsequent annual yield projections, we (Roleda et al unpublished data; Samson et al unpublished data) sampled most of the 51 sites during the April-May period, when oceanographic cruises are best carried out.…”

Section: Resultsmentioning

confidence: 99%

“…Harvesting the resource to determine natural stocks (e.g., Thomas et al 1975, Abanil et al 1984, GanzonFortes 1985, 1988, Fortes 1992 has seldom been used, since it is destructive and logistically more difficult. For instance, to avoid depleting the natural stock of the study area, Roleda et al (1997) estimated in situ biomass (i.e., g per 50 × 50cm) of the species by proportionately dividing the weight obtained from only one small grid (i.e., 10 × 10 cm) having the highest cover among a total of 25 grids. However, such an approach, though it may be highly practical, would be unrepresentative since the cover of a single grid ranges from 50-100% (see details in Saito and Atobe 1970).…”

Section: Introductionmentioning

confidence: 99%

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Estimating Biomass from the Cover of Gelidiella acerosa along the Coasts of Eastern Philippines

Rollon¹,

Samson²,

Roleda³

et al. 2003

Botanica Marina

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Estimating Biomass from the Cover of Gelidiella acerosa along the Coasts of Eastern Philippines

Rollon¹,

Samson²,

Roleda³

et al. 2003

Botanica Marina

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“…Gelidiella acerosa usually grows as submerged plant attached to calcareous substrata both in intertidal tide pools and shallow subtidal waters (Umamaheswara Rao 1973; Rama Rao & Subbaramaiah 1977; Ganzon‐Fortes 1985; Fortes 1991). The earlier studies have primarily focused on improvisation of extraction methods for obtaining improved agar yield and quality as well (Roleda et al . 1997a).…”

Section: Introductionmentioning

confidence: 99%

“…1997a). Despite its potential economic importance as an agarophyte, Gelidiella acerosa has only rarely been studied; some sporadic reports exist on the assessment of natural stocks of Gelidiella on the Philippines coast (Ganzon‐Fortes 1985, 1988; Fortes 1991; Roleda et al . 1997a) and Hawaii islands (Santelices 1978).…”

Section: Introductionmentioning

confidence: 99%

Seasonal variation in the biomass, quantity and quality of agar from Gelidiella acerosa (Forsskal) Feldmann et Hamel (Gelidiales, Rhodophyta) from the Gulf of Mannar Marine Biosphere Reserve, India

Ganesan

Reddy

Eswaran

et al. 2008

Phycological Research

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The Gulf of Mannar on the southeast coast of India, which has recently been declared as biosphere reserve, is the main harvesting place of Gelidiella acerosa for the Indian agar industry. The biomass harvested from natural stocks was estimated to be over 10 000 tonnes dry weight (DW) in the last two decades and is a serious cause of concern on long term sustainability of this valuable resource from this region. The present study reports the seasonal variation in the biomass and agar yield and quality from G. acerosa in four different habitats such as Rameswaram (rocky intertidal), Ervadi (lower intertidal), Sethukarai (subtidal) and Krusadai Island (lagoon reef area). A maximum biomass of 260 Ϯ 26 g DW m -2 was recorded from Ervadi, whereas Sethukarai showed the highest percentage cover (69.83 Ϯ 4.83%) and density (208.20 Ϯ 30.16 plants m -2 ). Biomass, percentage cover and density were lowest in Rameswaram and significantly lower (P < 0.001) than the other three stations. A single peak in biomass was observed with autumn maxima in Ervadi and Rameswaram and southwest monsoon maxima in Sethukarai and Krusaidai Island. Length of G. acerosa was maximum (9.65 Ϯ 0.25 cm) in Ervadi and the branch index value was maximum (24.70 Ϯ 4.01 br -1 g -1 DW) for Rameswaram. Agar yield (37.24 Ϯ 7.59%) and gel strength (448.66 Ϯ 6.50 g/cm 2 ) were higher in Sethukarai plants. The agar yields attained a peak in the northeast monsoon and decreased in summer, whereas a reverse trend was observed for gel strength. Evidently, agar yield showed a strong negative correlation with gel strength (P < 0.0001) and gelling (P < 0.0001) and melting temperatures (P < 0.01). The single annual peak in biomass observed in the present study, as compared with two peaks reported earlier, are attributed to the continuous overharvesting that would have had an effect on the overall annual biomass production. The findings of this study reveal that a single harvest during the autumn months (January to March) could yield optimum biomass with moderate agar and that would be the best for sustainable usage and conservation of this resource from this region.

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Effects of depth and initial fragment weights of Gracilaria gracilis on the growth, agar yield, quality, and biochemical composition

et al. 2018

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phycoerythrin is considered to be a predominant pigment in red algae. This pigment is at present used in food industry as colorant. Nevertheless, because of the spectral properties, it is used mainly in clinical and immunological analysis (Mensi et al.2012), in fluorescence microscopy and flux cytometry (Glazer and Stryer 1984;Kronick 1986). It is also reported that R-phycoerythrin and phycocyanin act as a part of protective mechanism in seaweeds in general (Sinha et al.1995) and in Gracilaria caudata particularly (Araujo et al.2014). To our best knowledge, few studies (Molloy and Bolton 1996;Mensi et al. 2009) were published regarding the effect of both depth and initial fragment weights on growth and proximate chemical composition of Gracilaria gracilis (previously known as G. verrucosa).Presently, there are neither large scale seaweed cultivation nor agar industry in Tunisia.Nevertheless, several attempts of Gracilaria farming were performed in the two last decades, using both spores (Ben Said and Aouini 2014) and cuttings/fragments (Ksouri et al.1999(Ksouri et al. , 2000 Mensi et al.2009). Four farming methods were used: ropes, sand filled plastic tubes, spade and suspended system in hoop-nets. On the other hand, some experimental agar extractions have been carried out on Gracilaria gracilis (Ben Said and Ksouri 1999; Ben Said et al.2015).This study aimed to determine the ability of Gracilaria gracilis to be cultivated at two different water depths in Bizerte lagoon, using net pockets. Additionally, relatively low initial fragment weights, compared with previously reported studies (Ksouri et al.1999(Ksouri et al. , 2000 Mensi et al.2009) were also tested in order to have an appreciable biomass with a high daily growth rate (DGR) in relation to environmental factors. The biomass could be firstly used for agar extraction and secondly for other potentially interesting compounds. Hence, agar yield, gel strength, gelling and melting temperatures were investigated because of their properties to

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Temporal Variation in the Biomass, Quantity and Quality of Agar from Gelidiella acerosa (Forsskål) Feldmann et Hamel (Rhodophyta: Gelidiales) from Cape Bolinao, NW Philippines

Cited by 12 publications

References 18 publications

Estimating Biomass from the Cover of Gelidiella acerosa along the Coasts of Eastern Philippines

Estimating Biomass from the Cover of Gelidiella acerosa along the Coasts of Eastern Philippines

Seasonal variation in the biomass, quantity and quality of agar from Gelidiella acerosa (Forsskal) Feldmann et Hamel (Gelidiales, Rhodophyta) from the Gulf of Mannar Marine Biosphere Reserve, India

Effects of depth and initial fragment weights of Gracilaria gracilis on the growth, agar yield, quality, and biochemical composition

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