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Department: search.filters.department.College of Arts and SciencesSDG: search.filters.sdg.SDG 14 - Life below water

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    Analysis of the gut contents of largehead hairtail, Trichiurus lepturus (Linnaeus, 1758) in Surigao Del Sur
    Barros, Andrea Philine R. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    The traditional gut content analysis is one of the methods used which investigates feeding interactions, specifically those belonging to the aquatic food webs. The ribbonfish, Trichiurus lepturus is an economically important fish, and due to its high demand to other south-east Asian countries especially in the Philippines, there is a targeted fishery for this resource. However, the catch of this species in the country has declined recently. Since feeding habits are fundamental to understanding the ecology of a community, this study aimed to analyze the gut contents of Trichiurus lepturus. A total of 66 guts were examined in the study. The size ranged from 101-505 mm in total length. They fed mostly on fishes including Encrasicholina sp., and shrimps such as Acetes, Penaeus, and Lucifer. Moreover, there was an occurrence of cannibalism but only larger individuals. Microplastics were also evident in most of the size classes.
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    Abundance, composition and distribution of phytoplankton in West Central Sulu Sea
    Bria, Jed B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2008-11)
    A total of 28 stations were sampled for abundance, composition and distribution of phytoplankton in the West Central Sulu Sea. The samples were taken from 15-30 April 2007. Samples were collected by filtering 50L of surface water through a 20 pm mesh plankton net. A total of 96 phytoplankton genera were identified and were grouped into four major taxa. The overall mean density was 444.6 cells/L. Diatoms were the most abundant, with the mean density of 213.5 cells/L. The most abundant diatom genus was Chaetoceros. Blue-green algae showed the second-highest mean density of 127.6 cells/L. Trichodesmium was the most abundant genus among the two blue-green algae identified. Trichodesmium was also the most abundant genus, comprising 28.1% of all phytoplankton identified. Dinoflagellates and silicoflagellates were ranked third and fourth among the four major taxa with 77.5 cells/L and 28 cells/L, respectively. Protoperidinium was the most abundant dinoflagellate, while Amphorella was the most abundant silicoflagellate. They made up 6.2% and 1.2 % of all phytoplankton identified, respectively. The stations located along the coast of Palawan and near the Tubattaha Reef Marine National Park showed the highest phytoplankton concentrations.
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    Influence of tidal levels on meiofaunal communities in a rocky shore area in Taklong Island National Marine Reserve, Guimaras
    Barbasa, Maria Carla A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2013-04)
    Rocky shores present an exuberant richness of life, which can be attributed to the hard substrate provided by rocks, necessary for the attachment of sessile organisms. There are many factors affecting community structure in rocky shores, including tidal levels. Tidal levels affect communities by periodically exposing them to air, causing drying up and dessication. Among those affected are meiofauna. Meiofauna in rocky shores are the least studied of all habitats, thus this study serves as baseline information regarding meiofauna in rocky shores, particularly in TINMAR, and how tidal levels affect them. Sorting and identification of meiofauna from 18 samples (5 TST, 5 TLT, 4 TMT, 4 THT) yielded 17 identified taxa, with Harpacticoids being numerically dominant followed by Tanaids (Copepods) and Polychaetes. Mean meiofaunal abundance was found to higher in lower tides (low and sub-tide), but differences were not statistically significant. A similar lack of significant differences between transects was shown for abundances of all and common taxa in edge or mid-section quadrats, although abundances appeared to be higher in low and sub-tidal transects. Cluster analyses based on similarities in abundance of taxa in the transect quadrats showed which asemblages are characteristic of mid- and high tide levels (Insect larvae and Sipunculids). Nematodes, which are typically dominant in soft-bottom substrates, were also most abundant in the upper intertidal in the present study. Other taxa like Tanaids, on the other hand, were more abundant in the low intertidal and subtidal transects. Harpacticoids were observed to be dominant in higher tides.
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    Gonadal maturation Stages of Pinkfingered Vinegar Crab Episesarma chengtongense (Serene and Soh 1967) from Capiz, Philippines
    Barredo, Elilyn Farrah Belle B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    The pink-fingered vinegar crab Episesarma chengtongense is a growing fishery resource in the mangrove areas of the Philippines and may have potential for aquaculture and stock enhancement. To determine the gonadal maturation stages for both male and female for this species, a study was conducted from February to May 2015 of the pink-fingered crab from Capiz, Philippines. The determination of the gonadal maturation stages was based on the gross morphology and histological characteristics of the male and female gonads. In both sexes, gonad activity occurred throughout the study duration but for females, the peak egg bearing month was in May (87%). Body sizes of ovierous females were from 31.9 - 42.3 mm (CW). The greatest prevalence of ovigerous females was in the size range of 35-39 mm CW; the lowest percentage at 40-44 mm CW. Male crabs with mature testes were consistently high (70- 100%) in the four months duration of the study. The smallest female carrying eggs was 31.9 mm CW. Four stages of ovarian maturation were identified namely: developing (Stage II) with a yellow colored gonad, ripe (Stage III) with orange colored gonad, mature (Stage IV) with brown colored gonad and spent (Stage V) with light brown colored gonad. Two stages of male gondal maturation were identified namely immature (Stage I) with translucent to off white testes and mature.(Stage II) with creamy white testes.
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    Gonadal maturation stages of pink-fingered vinegar crab, Episesarma chengtongense (Serene and SOH 1967), from Capiz, Philippines
    Ballon, Shaira B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Pink-fingered vinegar crab is a nocturnal, burrow-dwelling, and tree-climbing crab that feed on mangrove leaf litters and foliage. This crab is a growing fishery resource in the Philippines and plays an important role in the nutrient cycling in mangrove areas. To determine the reproductive biology of this species, a one-year study was conducted to monitor the gonadal maturation stages of the pink fingered crab from President Roxas, Capiz. Collection of samples was done every first week of the month from February 2015 to January 2016. The determination of the gonadal maturation stages was done through the visual examination of the gross morphology and microscopic examination of the histological characteristics of the male and female gonads. A total of 425 (263 females, 162 males) crabs were dissected. Five stages of ovarian maturation were identified based on visual examination of ovaries, namely Immature (Stage I) with translucent to white colored gonad; Developing (Stage II) with a yellow colored gonad; Ripe (Stage III) with orange colored gonad; Mature (Stage IV) with two substages, the Early mature (Substage A) with brown colored gonad and Late mature (Substage B) with dark brown colored gonad and; Spent (Stage V) with light brown colored gonad. Microscopic examination of the ovaries revealed that ovary in Stage I is characterized by the presence of germinative zone composed of oogonia and maturation zone composed of previtellogenic oocyte, surrounded by randomly distributed follicle cells. Ovary in Stage II is composed of few oogonia, previtellogenic cells, and few endogenous vitellogenic oocyte on the periphery of the ovarian lobe. Ovary in Stage III is composed of dominant exogenous vitellogenic oocyte located outer the few endogenous vitellogenic oocyte. Ovary in Stage IV-A is composed of nearly mature oocyte while in Stage IV-B is composed of mature oocyte. Ovary in Stage V is composed of all cell types, disarrayed in the entire ovarian lobe. Two stages of male gonadal maturation were identified namely Immature (Stage I) with translucent testes that is composed of spermatogonia and spermatocyte when histologically examined and Mature (Stage II) with white testes that is composed of small, darkly staining spermatids. Size of female crab samples ranged from 26 to 48.1 mm carapace width (CW) while male crabs ranges from 26 to 47 mm CW. The smallest ovigerous female has 29 mm CW and the smallest male with mature gonad has 26 mm CW. Body sizes of ovigerous females were from 29 to 42.3 mm CW. The greatest prevalence of ovigerous females was in the size range of 30 to 34 mm CW. The highest percentage of the mature stage (Stage II) in male was in the size range of 45 to 49 mm. For females, the peak egg bearing season was May (87%) and September (92%). On the other hand, male crabs with mature testes were consistently high (70 to 100%) in all months of the year. The results indicated that the months of May and September should be declared off season in the capture of female crabs ranging in size from 25 to 44 mm CW. Only big females in the size range of 44 to 49 mm CW could be harvested. Likewise, also male crabs in bigger size range of 45 to 49 mm CW could be harvested. This is necessary to protect and conserve the existing population of this crab.
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    Floristic composition and diversity of mangroves in selected sites in the province of Antique, Panay Island, Philippines.
    Balinas, Lucelle V. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2006-03)
    Mangroves in the Philippines are in constant danger due to innumerable disturbances in the environment. The study endeavored to assess the floristic composition and diversity of the mangroves in the province of Antique through transect and ocular survey in the randomly selected sites throughout the province. Diversity in the region is high with the presence of 3 1 true mangrove species represented by 16 families and 14 genera. The species include Acanthus ebracteatus, A. ilicifolius, and A. volubilis from Family Acanthaceae, Avicennia alba, A. marina. A. officinalis, and A. rhumphiana from Family Avicenniaceae, Camptostemon philippinensis from Family Bombaceae, Lumnitzera littorea and Lumnitzera racemosa from Family Combretaceae, Excoecaria agallocha from Family Euphorbiaceae, Pemphis acidula from Family Lythraceae, Xylocarpus granatum and Xylocarpus moluccensis from Family Meliaceae, Aegiceras corniculatum and Aegiceras floridum from Family Myrsinaceae, Osbornia octodonta of Family Myrtaceae, Nypa fruticans of Family Palmae, Bruguieria cvlindrica. B. gymnorrhiza, and B. sexangula, Ceriops decandra, C. tagal, Rhizophora apiculata. R. mucronata and R. stylosa from Family Rhizophoraceae, Scyphiphora hydrophvllaceae from Family Rubiaceae, Sonneratia alba, S. caseolaris and S. ovata from Family Sonneratiaceae, and Heritiera littoralis from Family Sterculiaceae . The Shannon Index of Diversity used to determine the measure of diversity in the area is correlated with Pielou's Equitability Index for Evenness. The measures of indices showed that diversity and evenness of the mangal area in the province are directly related, with values of 0.73232 and 0.51163, respectively. Caluya showed the highest diversity index of 1.0132, which consisted of 28 species from 13 families and 15 genera, while Bugasong has a relatively low diversity of 0.0486, denoted by 6 species from 4 families and 4 genera. In general, the high variations in the geomorphology of coastal areas in Antique provided a wide range of substrata for colonization of mangroves that contributed to the high species diversity.
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    Temporal variation in the subtidal macroinfaunal composition of a NaGISA seagrass bed in southern Guimaras, Philippines between 2015 and 2016
    Bacabac, Earl Jeroh I. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Seagrass meadows are amongst the most abundant and diverse ecosystems when it comes to biodiversity but due to stress induced by natural and anthropogenic factors, a worldwide decline threatens the vital ecological functions of these habitats. Studying the infauna provides clues and information about the complexity of seagrass ecosystems and provides information that would facilitate better seagrass area management and associated conservation efforts. The NaGISA sampling protocol was conducted in Calaparan seagrass bed in TINMAR, Guimaras, Philippines between Sept. 2015 and 2016. Overall macrofaunal density was recorded at 21,954.80 ± 36,109.62 ind.m'2 with macrofaunal density higher in 2015 than in 2016 albeit, insignificant except for capitellid polychaetes. Community structure analysis also found similarity in dominance patterns in the subtidal zone with other soft-bottom macrofaunal studies in the Philippines with polychaetes, nematodes, and crustaceans as the respective dominant macrofaunal groups observed. Dominant polychaete families were also found to be cosmopolitan and opportunistic. Granulometric analysis characterized the sediment as pebble to medium sand with mid phi values ranging from -3.69 to 1.10 but poor sorting in all sampling points was observed. Cymodoceaceans dominated the subtidal zone in both years (Halodule pinnifolia in 2015; Cymodocea rotundata in 2016). Correlation analysis showed macrofaunal densities to have a significantly strong negative relationship with sorting index and percent gravel while a strong positive relationship with percent seagrass cover. The poor sediment sorting, coarse sediment character, and seagrass cover were the primary factors influencing the observed decrease in macrofaunal density but the decrease is considered normal for the variability of macrofauna in the area. A clearer picture of macrofaunal interactions would be provided with comparison to intertidal macrofauna of the area in the sampling years and data on additional factors that were not measured in the study.
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    Molluscicidal activity of tabaco dust against the brackishwater pond snail Telescopium telescopium (Gastropoda: Potamididae)
    Azucena, Paulene C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-04)
    Telescopium telescopium, a molluscan potamidid snail thrives in the muddy substrates of brackishwater ponds in the Philippines. It occurs in considerable numbers but uncontrollable increases in its population poses serious threats to pond production. Tobacco dust is considered as a potential biomolluscicide that is able to control pond snail infestation. A short-term bioassay was conducted to know the effectiveness of tobacco dust as a molluscicide against T. telescopium by determining its median lethal concentration (LC50) after a period of 96 hours. Twenty-five telescope snails were subjected to varying concentrations of tobacco dust, from 0 to 1.0 kg/L at 0.2-kg increments. Three replicates were done for every treatment. Counting of dead snails was done after 48 and 96 hours of exposure. Snails exposed to varying concentrations of tobacco dust exhibited several defense mechanisms such as avoiding the toxic solution by crawling out of the area, closing their operculum and retracting their bodies toward their shell. Highest snail mortality was observed at the 1.0-kg/L treatment. After the 96-hr. exposure time, the concentration of tobacco dust that proves to be lethal to 50% of the snails was computed to be 0.5849 kg/L. Indeed, tobacco dust is an effective molluscicide against brackishwater pond snails, particularly T. telescopium.
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    Acute toxicity of polysolve oil dispersant to Nile tilapia (Oreochromis niloticus Linn.) fry
    Atas, Bryan B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2011-03)
    Forty eight hour (48h) static bioassays were conducted to determine the toxicity of Polysolve oil dispersant to Nile tilapia (Oreochromis niloticus) fry. Median lethal concentrations (LC50) were 1.03, 0.79, 0.70, 0.45, and 0.39% for 24, 30, 42, and 48h, respectively. Polysolve is highly toxic to Nile tilapia fry at low concentrations. Results showed increasing toxicity over increasing length of exposure. It is therefore recommended that Polysolve must not be used in oil spill response. Sublethal effects of the dispersant on the fry include decreased activity and impaired responses
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    Comparison of the length-weight relationship between starved and fed Scylla tranquebarica crablets
    Arroyo. Ritchel B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-04)
    This study aimed to determine the length-weight as well as the width-weight relationships of the Scylla tranquebarica crablets when starved and fed during the intermolt and premolt stages. Molt stages were identified and then the crablets were subjected to feeding or starvation for 36 days. Regression analysis showed the length-weight relationship of the Scylla tranquebarica crablets, including carapace length, carapace width, and body weight when fed and starved. Regression lines for each category differed from one another. Results showed that the fed crablets in intermolt and premolt stages showed greater body weight gain per unit carapace length and carapace width. The intermolt fed gave the highest weight gain per unit length and unit width among the treatments. Equations for interconversions of length and weight and for length and width are reported for the premolt and intermolt stages when fed and starved.