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UPV Theses and Dissertations

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    Abundance, composition and vertical distribution of calanoid copepods in Central Sulu sea
    Burgos, Lora A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Calanoid copepods are dominant component of the copepod community, which in turn highlights their influence on the overall zooplankton assemblage of the water column. Studying their abundance and distribution, is important on understanding their role in the dynamics of commercially important organism like the fish. Calanoid samples in study, were part of the zooplankton samples taken during the Joint PhilEx oceanographic cruise on board RAZ Melville in December 2007 in the Central Sulu Sea from MOCNESS station 29. Calanoid abundance, composition and distribution were investigated. Fifteen (15) calanoid families were identified all throughout the water column (0 - 400 m). The calanoid assemblage was dominated by 27 % Eucalanidae, 12 % Rhincalanidae, Scolecitrichidae with 7 % and other families contributing to roughly 19 % of the total. The water column was divided into 2 distinct depth cluster based on species distributions; (1) layers above thermocline (0 - 150m) and (2) deeper layers (200 - 400m). Furthermore, upper layers were characterized by distinctive calanoid family assemblage which includes; Calanidae, Euchaetidae, Eucalanidae, Candaciidae, Rhincalanidae, and Temoridae. While deeper layers, calanoid families includes; Metridinidae, Scolecitrichidae, Rhincalanidae, and Euchaetidae. ANOSIM results showed significant differences between these depth clusters, with global R = 0.81 and p = 0.01. These appear to be highly related to the thermocline in both stations, where typically higher upper-layer primary productivity can support dense communities of zooplankton.
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    Zooplankton composition, abundance and diversity in selected Municipalities of Negros Occidental and Aklan
    Ausan, Aisa Marie U. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Zooplankton samples were collected last May and June 2014 from 20 stations in the vicinity of Kalibo, Aklan and Pontevedra, San Enrique, and Valladolid, Negros Occidental. Three hundred fifty-three (353) liters of water were filtered per station thru a 5m vertical haul of plankton net with a diameter of 30cm and a mesh size of 20μm. Overall zooplankton densities were higher in Negros Occidental, specifically in Valladolid (D=1915.3 cells/L), than in Kalibo, Aklan (D=7.2 cells/L). On the other hand, zooplankton community was most diverse in Kalibo (H’ = 2.6) compared to Valladolid (H’=1.3), San Enrique (H’=2.1) and Pontevedra (H’=1.8). Jaccard’s similarity index was highest between Pontevedra and San Enrique while lowest between Valladolid and Kalibo. In Kalibo there were four major groups of zooplankton. Most dense of these were the tintinnids (3.9 cells/L) followed by copepods (2.5 cells/L), molluscs (7xlOE-lcells/L) and polychaetes (IxlOE-lcell/L). Among the copepods Subeucalanus was the most abundant zooplankton genus. In Pontevedra and San Enrique, Negros Occidental, copepods were the most abundant group with a mean density of 205.3 cells/L and 312.1 cells/L, respectively. The relative abundance ofAcartia (36.5%) and Longipedia (22.6%) made them the dominant zooplankton genera in Pontevedra and San Enrique, respectively. Like in Kalibo, the tintinnids were also the most abundant group in Valladolid (1879.2 cells/L). Copepods followed with a mean density of 35.7 cells/L, while Polychaetes comprised only 4xlOE-l cells/L. Epiplocylis was the most abundant tintinnid in Valladolid while Xystonella in Kalibo. Varying sampling time within months and day is the possible cause of the differences in zooplankton abundance, composition, and diversity since some zooplankton species undergo diel vertical migration.
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    Influence of lunar cycle and tidal fluctuation of gonadal maturity of green mussel (Pema viridis) in Inner Malampaya Sound, Taytay, Palawan
    Baldevieso, Adzel Adrian G. (University of the Philippines Visayas, 2018-07)
    This study aims to identify the ideal period of harvesting cultured green mussel (Perna viridis) in order to attain larger flesh to shell ratio in inner Malampaya Sound, Taytay, Palawan by investigating the gonadal maturity in relationship to lunar cycle, tides, physicochemical and water productivity parameters. Twenty green mussel samples undergo histological analysis of gonad and 50 samples were measured for body indices weekly from October 2017 to March 2018. Results showed that the body and gonad indices have significant positive correlation with slight higher values during the first quarter weeks, and during a day before the low low tides. The peak of spawning was recorded during October. After which, partial spawning was observed and starts during the weeks of full moon until new moon with a duration of 1-3 week. Thus, the gonadal development/maturity of green mussel in the study is influenced by lunar cycle and tidal fluctuations. Among the water parameters monitored, salinity, pH, and temperature have a significant difference in the monthly, and lunar weeks levels. Furthermore, the drop in salinity might trigger the peak spawning. Diatoms (91%) dominate the plankton composition in the sampling area followed by small percentage of dinoflagellates (4%), zooplankton (2%), and cyanobacteria (2%) and ciliates (1%). The genus Coscinodiscus has the highest percentage (97.73%) among the diatom genera, this species could be one of the major algal diet of green mussels in the area. On the other hand, there was no significant correlation between the gonad index and body indices to the physicochemical parameters and water productivity parameters. Based on body indices and gonad index values, the ideal period to harvest green mussel is during the first quarter weeks. One out of 540 samples was found to be hermaphrodite.
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    Semiparametric and parametric modelling of vibro species abundance production system
    Dequito, Angel Queenee D. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2017-09)
    Vibrio species that cause white spot disease and vibriosis are known to be influenced by environmental factors. In this study, the changes in the abundance of presumptive Vibrio species from a biofloc shrimp production system with respect to physicochemical and biological parameters were evaluated. Parametric and nonparametric modelling techniques were used to identify and predict changes in Vibrio abundance in relation to alkalinity, ammonia, dissolved oxygen, nitrite, pH, salinity, temperature, transparency, and phytoplankton and zooplankton densities. Abundance was found to be highly correlated with alkalinity, pH, and phytoplankton density as revealed by both parametric and semiparametric models. Generalized additive model (GAM, a semiparametric model) is the best model based on Aikaike’s Information Criterion (AIC) values in which 41.2% of the variability in the dependent variable can be explained by the predictors compared to ordinary linear regression and negative binomial models (parametric models) with 16.04% and 14.5% respectively. Prediction on the abundance can help prevent bacterial diseases in shrimp as this will provide an insight to the farmer about when to and which water parameters or predictors can be controlled. Thus, it is important to consider the use of semiparametric modelling approach as a tool for fish health management and to prevent losses in aquaculture.