Assessment of Stocks of a Natural Gracilaria Population on Panay Island, Philippines

Castro, T. R. de; Guanzon, Nicolas G.; Luhan, Ma. R. J.

doi:10.1515/botm.1991.34.5.383

Cited by 13 publications

(3 citation statements)

References 9 publications

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“…Salinity negatively affects the growth of Gracilaria. The negative correlation observed between growth and salinity is in agreement with De Castro et al (1991). According to Bird and McLachlan (1986), most Gracilaria species are euryhaline, however, the optimal salinity level required for growth is speciesspecific.…”

Section: Discussionsupporting

confidence: 73%

Some Aspects of the Growth of Gracilaria birdiae (Gracilariales, Rhodophyta) in an Estuary in Northeast Brazil

2006

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The agarophyte Gracilaria birdiae Plastino & Oliveira was cultivated under field conditions in an estuary over a 6-month period. Biomass production varied significantly (p<0.01) and ranged from 900.0 to 3537.0 g m )2 with a mean of 2124.4±1004.36 g m )2 over the cultivation period. The epiphyte-biomass varied from 64.7 to 313 g m )2 , with maximum values observed in July. Relative growth rate (RGR) of G. birdiae varying from )0.59 to 4.67% day )1 , with a maximum mean observed in July. Correlation analysis showed that RGR was positively correlated with epiphyte-biomass (R-Pearson=0.69; p< 0.01) and negatively correlated with salinity (R-Pearson=)0.41; p<0.05). These correlations were used in a mathematical regression model to estimate the growth of Gracilaria in an estuary. The regression model explained 61% of RGR variability demonstrating that growth rates of Gracilaria were directly related to the variables salinity and epiphytes. The model was developed to help to predict production at a cultivation site in order to evaluate its suitability for Gracilaria cultivation.

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Section: Discussionsupporting

confidence: 73%

Some Aspects of the Growth of Gracilaria birdiae (Gracilariales, Rhodophyta) in an Estuary in Northeast Brazil

2006

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“…The study was conducted at the Igang Marine Station of the Aquaculture Department of the Southeast (Trono et al 1983), was chosen for this study because it is found abundantly in natural beds on Panay Island, Philippines (de Castro et aL 1991). Seedstocks were collected from Kulong-kulong, Zarraga, Iloilo, Philippines.…”

Section: Methodsmentioning

confidence: 99%

The Effects of Different Stocking Densities and Some Abiotic Factors on Cage Culture of Gracilaria sp. (Rhodophyta, Gigartinales)

Guanzon¹,

Castro²

1992

Botm

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Specific growth rates (% day" 1 ) and production rates (gm~2 day" 1 ) of Gracilaria sp. reared in net cages on a bamboo floating raft from March 1989 to February 1990 were determined at different stocking densities (200, 250, 300 and 350 g 0.5 m~2/net cage). Mean specific growth rates for the whole culture period were highest at stocking densities of 200 and 250 g 0.5 m" 2 (P < 0.05). Highest mean net production rate was obtained at a stocking density of 250 g 0.5 m~2, but was not significantly different from stocking densities of 300 and 350 g 0.5 m 2 (P < 0.05). Highest monthly mean specific growth rates and monthly mean net production rates for all treatments were obtained during March and November 1989 and February 1990. There were no significant differences (P > 0.05) in monthly mean specific growth rates and mean net production rates between the three peak months, although they were significantly different from the rest of the months (P < 0.05). Production was higher during the dry season. Correlation analysis showed that total rainfall was negatively correlated with specific growth rate and production rate. Salinity, temperature and pH were not correlated with specific growth rate and production rate.

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“…4. It seems that they are responders (1977), Black & Fonck (1981), Boraso de Zaixso (1990), Castro et al (1991), ChennubhotlaetaL (1986), Conover, 1958), Dellarossaetal. At low latitudes, in the populations considered, monsoons control seasonality and the peak occurs mainly in the 'winter' but may be bimodal (Jayasuriya, 1993;Kaliaperumal et al, 1986;Umamaheswara Rao, 1973).…”

Section: Seasonal Growthmentioning

confidence: 99%

A review of the life history, reproduction and phenology of Gracilaria

1995

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The basic life history of the red alga Gracilaria is of the three-phase Polysiphonia type but a number of species show deviations. Plants can bear both gametangia and tetrasporangia, either on separate parts of the thallus or on the same. Explanations include the in situ germination of tetraspores (allowing gametophytic thalli to be epiphytic on tetrasporophytes), the coalescence of spores or developing discs (resulting in chimaeras), mitotic recombination during cell division in the mature diploid thallus (resulting in patches of diploid male and female cells on the tetrasporophyte), a mutation eliminating the repression of female expression allowing haploid male plants to be bisexual and initial failure of cell walls to form during the development of tetraspores. Polyploids can be produced from plants with diploid gametangia. The sexes and phases are usually morphologically identical but gametophytes or their parts may be smaller. The growth rates of the sexes may differ and diploid juveniles may survive better than haploid. Neither polyploidy nor hybridization results in superior growth. The sex ratio is probably 1:1 but females may appear to be more abundant. Diploid and haploid phases are usually either about equal or diploids predominate, often depending on the type of substratum. At high latitudes reproduction peaks in late summer whereas in the tropics it may be high all year. In temperate regions growth rate is fastest and biomass highest in late summer; in the tropics peak biomass is mainly in the winter. Spermatia are effective for only a few h. Spores vary in size around 25 Am, diploid ones usually being larger. Cystocarps or tetrasporangia in the field may not currently be releasing spores. In the laboratory spore release shows a diurnal rhythm, peaking during the night or day according to the species. All the above attributes are potentially important in planning and executing Gracilaria cultivation.

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Assessment of Stocks of a Natural Gracilaria Population on Panay Island, Philippines

Cited by 13 publications

References 9 publications

Some Aspects of the Growth of Gracilaria birdiae (Gracilariales, Rhodophyta) in an Estuary in Northeast Brazil

Some Aspects of the Growth of Gracilaria birdiae (Gracilariales, Rhodophyta) in an Estuary in Northeast Brazil

The Effects of Different Stocking Densities and Some Abiotic Factors on Cage Culture of Gracilaria sp. (Rhodophyta, Gigartinales)

A review of the life history, reproduction and phenology of Gracilaria

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