Journal Articles - UP - MSI

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Effect of desiccation on Tridacna derasa seed: Implications for long distance transport
Lopez, M.D.G.; Heslinga, G.A. (Elsevier BV, 1985-11)
Savings in freight cost from removal of the byssus and adherent material from T. derasa seed may not offset man-hours required for pre-shipment preparation, and decreased seed viability.
Spontaneous maturation and spawning of milkfish in floating net cages
Marte, Clarissa L.; Lacanilao, Flor (Elsevier, 1986-04)
Milkfish (Chanos chanos Forsskal) reared from wild-caught fry and from hatchery-bred fry matured at 3.5–5.5 years (2.3–4.9 kg). Maturation and spawning of the hatcherybred fish marks the first time the milkfish life-cycle has been completed in captivity. Milkfish at various stages of gonadal development were obtained in July–October 1980 and March–June 1981 derived from wild-caught fry, and in February–June 1983 from the hatchery-bred fish. The fish were held in floating net cages 9 m and 10 m diameter by 3 m deep, located in 7 m deep water off Igang, Guimaras Island, Philippines. Annual ranges of temperature and salinity were 25–33°C and 25–38 ppt, respectively. The fish were fed commercial feed pellet (42% protein) at 1.5–2% of body weight twice daily. Sexual maturation occurred during the natural breeding season of wild milkfish in the nearby waters. Gonadosomatic index (GSI) of mature males was 0.32–3.95 (wild-caught, 0.32–3.95; hatchery-bred, 1.71–3.85). For mature females it was 1.24–8.12 (wildcaught, 1.56–7.62; hatchery-bred, 1.24–8.12). Two spawnings were recorded in August 1980 and eight in May–July 1981 from the broodstock derived from wild-caught fry, with 342–6293 eggs collected from each spawning, while 14 spawnings were observed in May–June 1983 from the hatchery-bred fish, with 770–114 000 eggs collected. The time of spawning was between 23.00 and 02.00 h. Fertilization rate was 55–99% for the broodstock from wild-caught fry and 47–100% for the hatchery-bred fish. Hatch rate varied from 9 to 80%. Factors affecting spontaneous maturation, spawning and rematuration are discussed. Although slight improvements in egg collection were obtained, further innovations in egg collecting techniques will have to be developed. The results indicate the potential for hatchery production of milkfish fry from captive broodstock and for restocking of waters deprived of naturally occurring fry.
Electrophoretic evidence for extensive hybrid gene introgression into commercial Oreochromis niloticus (L.) stocks in the Philippines
Macaranas, J. M.; Taniguchi, N.; Pante, M. J. R.; Capili, J. B.; Pullin, R. S. V. (Hindawi Limited, 1986-10)
The usefulness of isozyme and protein markers in identifying tilapia species and their hybrids is demonstrated. Genetic characterization of Oreochromis niloticus populations from commercial farms, experimental stations, and government hatcheries in Luzon, Visayas and Mindanao in the Philippines indicates well-established introgression with O. mossambicus. Genetic differentiation of the O. niloticus stocks, measured by Nei's genetic distance, was highly correlated with O. mossambicus gene content. The implications of these results for tilapia genetic improvement are discussed.
The genus Sargassum (Phaeophyta, Sargassaceae) from Balibago, Calatagan, Philippines
Ang, P. O.; Trono, G. C. (Walter de Gruyter GmbH, 1987)
Eight species of Sargassum: S. baccularia (Mertens) C. Agardh, S. cinctum J. Agardh, S. crassifolium J. A-gardh, S. ilicifolium (Turner) C. Agardh, S. notarisii Zanardini, S. oligocystum Montagne, S. paniculatum J. Agardh, and S. siliquosum J. Agardh are reported from Balibago, Calatagan, Philippines. Growth and changes in the morphology of the two most common species, S. paniculatum and S. siliquosum, were noted throughout their different growth phases over 1 1/2 years. Collections of material representing growth stages of the other species were made at periodic intervals. The more consistent morphological characters for each species were recognized and their utility in taxonomic work was discussed. These characters include outline and length/width ratio of the leaves characteristic of each branching order of laterals, shape and size of the vesicles, muricatous nature of the terminal branchlets, branching pattern of the receptacles, morphology of the female receptacles and the type of holdfast.
Indo-West Pacific affinities of Philippine seagrasses
Fortes, M. D. (Walter de Gruyter, 1988)
A dendrograph was developed to depict the mutual relationships among 27 Indo-Pacific countries with similar seagrass floras. Hierarchical (cluster) analysis of the resulting affinities provides strong evidence that the countries could be partitioned into seven discrete provinces. The genus Halophila represents a major connection between most of these provinces, strongly influencing the clustering of the Seagrasses. The degree of species overlap (9.5 — 46.2%) between Province A (where Philippines belongs) and Province G (Western, Southern, and Southeastern portions of Australia) favors vicariance as an explanation. The separation of Kampuchea as a discrete unit within Province A appears to be an artifact of collection rather than a reflection of the true floral affinities in the region. The lack of sufficient basic floristic information remains as the most serious limitation in any attempt to describe the phytogeographic affinities of seagrasses in the Indo-Pacific region.
A comparison of two benthic survey methods
Mingoa, S. S. M.; Menez, L. A. B. (Springer, 1988)
The belt transect and the flowmeter methods, used to survey sedentary benthic organisms, were compared based on abundance estimates of tridacnid clams in the Cagayan Islands, Philippines, in April 1985. Two-way ANOVA and chi-square tests (P<0.05) show that both methods recorded similar estimates for the number of clams (regardless of species), both methods gave similar estimates for the number of individuals per species, and one or both methods may be biased for certain sizes of clams. Individuals smaller than 6 cm shell length seemed to be underestimated by the flowmeter method. Future studies must investigate the size selectivity of the method used, for instance by conducting permanent belt, transect surveys of varied belt widths (e.g. 1, 1.5,2,2.5 m) and then comparing the recorded lengths of the most abundant clams. This will aid investigators to evaluate their data properly, and enable comparison of clam-stock estimates between surveys.
Growth rates and primary production of Enhalus acoroides (L.f.) royle from Lag-it, North Bais Bay, the Philippines
Estacion, Janet S.; Fortes, Miguel D. (Elsevier, 1988-01)
The growth rates and primary production of the leaves of Enhalus acoroides (L.f.) Royle at Lag-it, North Bais Bay, The Philippines, were studied from August 1982 to August 1983. Randomized complete block design showed that both rates are considerably influenced by the composite effect of spatial and temporal factors. Similarly, both are markedly bimodal. Mean growth rate was 0.93 cm day−1, with peaks in September–October and May, with lowest values in November–January. Mean production was 0.92 g C m−2 day−1, with peaks in October and March–May (Station 2) and December (Station 1) and lowest values in December (Station 2) and in June (Station 1). Growth rates significantly increased with a decrease in the percent of time the seagrass beds were exposed to air and sun in the daytime (r=−0.69), while it increased with the number of daylight hours (r=0.72). Production showed no significant correlation with either factor. Mean turnover time for the seagrass was 67 days, producing 5.5 crops annually.
Temperature-influenced infection rates in the Chondrus crispus-Petersenia pollagaster pathosystem: A regression analysis
Molina, F. I.; Hughes, G. C.; Craigie, J. S. (Springer, 1988-03)
Cross-infection experiments were performed to determine the influence of temperature on infection rate in the Chondrus crispus Stackhouse-Petersenia pollagaster (Petersen) Sparrow pathosystem. C. crispus thalli were collected at Pubnico Harbor, Nova Scotia, Canada in the fall of 1981 to 1984. Infective zoospores were used to inoculate healthy thalli at five different temperatures. The highest infection rate was obtained at 20°C, while significantly lower rates were obtained at temperature extremes. The parasite's life cycle, consisting of infection of healthy thalli, endobiotic development, and release of zoospores, was completed in 48 to 72 h at 15° to 20°C.
Fishing mortality rates of giant clams (Family Tridacnidae) from the Sulu Archipelago and Southern Palawan, Philippines
Villanoy, Cesar L.; Juinio, Antoinette R.; Meñez, Lambert Anthony (Springer, 1988-05)
Average size frequency distributions of Tridacna squamosa, T. gigas, Hippopus hippopus and H. porcellanus harvested from the Sulu Archipelago and Southern Palawan areas from 1978–1985 were derived from export records and a warehouse inventory of giant clam shells. Average species mortality rates (Z) were estimated and were used to approximate average fishing mortality rates (F) over the period 1978–1985. Crude estimates of exploitation rates (F/Z) indicate that populations of these species are already overexploited. These findings have serious implications in view of the fact that the Sulu Archipelago and Southern Palawan are thought to be the last strongholds of giant clams in Philippine waters.
Notes on the induced spawning and larval rearing of the Asian moon scallop, Amusium pleuronectes (Linné), in the laboratory
Belda, C. A.; Del Norte, A. G. C. (Elsevier, 1988-08)
Sexual and chemical stimulations were effective in inducing the scallop, Amusium pleuronectes (Linné), to spawn sperm only, whereas thermal stimulation was not at all successful. Chemical stimulation consisted of serotonin injections into the ripe gonads. Fertilizable eggs were obtained by stripping gametes from the ovaries. Cleavage of zygotes (72.4 μm mean diameter) occured 1 h after fertilization. Trochophores (58.9–111.2 μm in length) and straight-hinge veligers or D-veligers (80.0–130.2 μm) were observed in less than 24 h. Five days after fertilization, the umbone stage (101.6–169.1 μm) was reached. Crawling pediveligers (174.0–250.0 μm) appeared after 9 days. Seawater in the culture vessels was changed 24 h after fertilization and every other day thereafter. The larvae were fed on Isochrysis galbana (Tahitian strain) at an initial concentration of 30 cells/gml.
Aspects of the growth, recruitment, mortality and reproduction of the scallop Amusium pleuronectes (Linné) in the Lingayen Gulf, Philippines
Del Norte, A. G. C. (Informa UK Limited, 1988-11)
Growth, recruitment, mortality and reproduction were investigated in the Asian moon scallop, Amusium pleuronectes (Linne) from the Lingayen Gulf, Philippines. Allometric relationships were defined by comparing different shell dimensions, as well as body weight proportions including total weight with shell, visceral weight, adductor muscle weight and gonad weight. Use of the von Bertalanffy-based ELEFAN I program yielded estimates of growth parameters equivalent to H ∞ = 106Dimshell height and K = 0.92 per year, with approximate longevity for the species of about 2 years. Recruitment, as derived using the ELEFAN II program, occurred throughout the year, but showed a pattern consisting of one major and one minor pulse separated by an 8- and 4-months interval. Fishing mortality (F = 5.3) was higher than natural mortality (M = 1.9). Spawning occurred throughout the year, with one major peak in February and one minor peak between July and September, thereby providing some biological basis to the recruitment pattern indicated. Protandry and size at sexual maturity (54 mm) in the species were confirmed.
Wound healing in cultured Eucheuma alvareziivar. tambalang Doty
Azanza-Corrales, R.; Dawes, C. J. (Walter de Gruyter GmbH, 1989)
Wound healing in segments of Eucheuma alvarezii var. tambalang grown in enriched media in the laboratory can be divided into four stages based on histological and cytological changes. During the first stage, approximately 2—4 days after wounding, proteinaceous and phenolic substances concentrate on pit plugs of cells adjacent to the wounded surface. In the second stage, about the sixth day, cellular extensions are produced from the pits of medullary and cortical cells of sub-wound layer. During the third stage, about the 8th day, the cellular extensions divide several times and elongate towards the surface. A new cortical or wound tissue is formed during the fourth stage beginning on the 12th day. The wound tissue is continuous with the old cortex within 3 weeks.
Status of giant clam resources of the Philippines
Juinio, Marie Antoinette R.; Meñez, Lambert Anthony B.; Villanoy, Cesar L.; Gomez, Edgardo D. (Oxford University Press (OUP), 1989-11-01)
Field surveys were conducted to determine distribution and abundance of giant dam resources in the Philippines. All seven known species of giant clams were recorded with Tridacna crocea, T. maxima and T. squamosa occurring the most frequently. The larger species T. derasa, T. gigas, Hippopus hippopus and H. porcellanus were relatively rare. The reduction of giant dam stocks in the Philippines is due to the uncontrolled exploitation of this resource which is primarily gathered for shellcraft and as supplementary diet in coastal villages.
Water quality bioassays in two Bermudan harbours using the ciliate Euplotes vannus, in relation to tributyltin distribution
Slabbing, A. R. D.; Soria, S.; Burt, G. R.; Cleary, J. J. (Elsevier, 1990-01)
Laboratory cultures of the ciliate Euplotes vannus were used to bioassay water samples taken from the sea surface, 0.5 m and near bottom at stations along contamination gradients in Castle Harbour and Hamilton Harbour on Bermuda. Inhibition of population growth rate was used as an index of exposure to toxic contaminants. Significant differences in growth rates from near-bottom water samples taken at two stations in Castle Harbour were reflected in differing sediment concentrations of metals and petroleum hydrocarbons. Bioassays of four Hamilton Harbour samples indicated significant differences between control and contaminated sites when results from all three depths were pooled. Highest concentrations of tributyltin (⩽ 307 ng TBT·1−1) occurred in the surface microlayer, though measurements varied widely on the two sampling occasions. At 0.5 m, concentrations were much less variable and showed a steady decline from the head of Hamilton Harbour (41 ng TBT· 1−1) seawards to the control site (0.9 ng TBT · 1−1). While these concentrations are high enough to be toxic to some species, it is known from experimental work that TBT alone could not have accounted for the depression of ciliate growth rates in these bioassays.
Strain differences in cultured fish — Isozymes and performance traits as indicators
Macaranas, J.; Fujio, Y. (Elsevier BV, 1990-03)
A comparison of genetic changes in broodstocks or strains of five cultured fish species, namely, Japanese char, Nile tilapia, Mossambica tilapia, Japanese common carp, and the guppy, showed them to be influenced by the intensity of selection pressure and/or by the history of culture. Allele distributions at polymorphic loci were mainly governed by genetic drift and also by introgressive hybridization or gene exchange. Such genetic changes are expected to occur also at loci controlling performance traits. Using the guppy, Poecilia reticulata, as a model fish, 10 different strains consciously selected for body colour patterns, body size, and finnage, and which were genetically differentiated into six race level groups, were investigated for strain differences in eight growth-related and reproductive traits. Strain differences were significant for all traits and phenotypic differences, expressed as [d]m='P1 - P2||(P1 + P2), were significant in at least one out of eight traits for every strain pair. Of the eight quantitative traits, survival at Day 60, fertility ratio, and brood size showed higher variation, as seen from their coefficients of variation and [d]m range. The correlation of overall [d]m between strains and their corresponding Nei's genetic distance was low (r = −0.104) but individual trait correlations with Nei's D were significant for survival at Day 0 and male body length at Day 60. Results suggest that strain differences are characterized by a random segregation of alleles both at biochemical and trait loci but that occasionally, linkage may occur. The utility of isozyme markers and [d]m the index are discussed.
The farmed Euchema species in Danajon Reef, Philippines: Vegetative and reproductive structures
Azanza-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.
Seasonality of standing crop of a Sargassum (Fucales, Phaeophyta) bed in Bolinao, Pangasinan, Philippines
Trono, Gavino C.; Lluisma, Arturo O. (Springer, 1990-09)
The seasonality of standing crop of a Sargassum bed was investigated by conducting monthly sampling from February 1988 to July 1989. Environmental parameters of water movement, salinity, number of daytime minus tides, and water temperature were also measured. An intra-annual pattern of variation in standing crop of Sargassum crassifolium, S. cristaefolium, S. oligocystum, and S. polycystum was observed. Standing crop was generally lowest in February, March, April, or May, and highest in November through January. Sargassum accounted for about 35 to 85% of the monthly algal standing crop of the bed, and the observed variation in overall standing crop of the bed generally reflected the standing crop of Sargassum. The seasonality of the standing crops of the associated algal divisions also followed an annual cycle, but their maximum and minimum standing crops did not coincide with those of Sargassum. Individually, as well as collectively, the standing crops of the Sargassum spp. were poorly correlated with the environmental factors observed.
The farmed Eucheuma species (Gigartinales, Rhodophyta) in Danajon Reef, Philippines: Carrageenan properties
Azanza-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.
Influence of Bass Strait water on the Tasman Sea thermocline
Villanoy, C. L.; Tomczak, M. (CSIRO Publishing, 1991)
Volumetric analysis of the Tasman Sea Central Water for different temperatures and salinities was used to determine the degree of influence of the seasonal outflow from Bass Strait on the observed strong positive anomalies in the Tasman Sea thermocline. The absence of a systematic decrease of salinity and Bass Strait Water content away from the coast suggests that the observed high-salinity anomalies are not entirely manifestations of Bass Strait Water alone and that some local processes may be involved in modifying the water properties. It is suggested that the seasonal Bass Strait Water intrusions may act as a trigger to overturn the environment, entraining high-salinity water from the upper layers by double-diffusive convection.
Seagrass-mangrove ecosystems management: A key to marine coastal conservation in the ASEAN region
Fortes, Miguel D. (Elsevier, 1991-01)
Seagrass beds and mangrove forests are intimately linked by functional interactive processes which are as yet little understood. These high-order interactions form a major basis which justifies an integrated management scheme for the two ecosystems. However, while dominating enclosed coastal areas in the ASEAN region, seagrass and mangrove habitats are being degraded and destroyed at an alarming rate, raising serious doubt on their capacity for biological sustainability and normal recovery within this generation. An integrated approach towards seagrass and mangrove ecosystems management in the ASEAN region is discussed within a framework of known ecological principles. Recommendations are made for the conservation and sustainable use of the ecosystems and their resources.