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    Rock-associated Cryptofauna in Seagrass Beds in Taklong Island National Marine Reserve, Guimaras, Philippines
    Camache, Christian M. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    It has been suggested that cryptofauna makes up the bulk of marine ecosystems. Little is known of the ecology of cryptofauna and the few studies conducted about them stress their importance in the ecology of marine systems. This study was conducted to assess the biodiversity of rock-associated cryptofauna in seagrass beds in the Taklong Island National Marine Reserve (TINMR) and to correlate their abundance and diversity to the rugosity of the substrate. Rock samples were collected from three seagrass beds, namely: Calaparan, Kalirohan, and Bagatnan. The cryptofauna inhabiting the rock samples were extracted using forceps and were then sorted into major taxonomic groups and identified. The density of each taxonomic group, the diversity and similarity indices of and among sites, and the rugosity and volume of the rock samples were calculated. A total of 2,255 individuals were collected belonging to 97 OTUs and eight major taxonomic groups, with a mean density of 1.13±0.51 indiv/mL. Foraminiferans and crustaceans were the most prominent organisms observed in all sites while polychaetes showed significant density variations. Cryptic fauna diversity was low in all sites. Kalirohan had the highest diversity index (H’ = 0.86 ± 0.119) while Calaparan had the lowest (H’ = 0.67 ± 0.125). All sites showed low similarity coefficients with Kalirohan and Bagatnan showing the highest value (31% similarity). No significant correlation was found between the rugosity of rock substrates and density of cryptofauna contrary to expected trend. This suggests that rugosity may not be a key determinant of cryptofaunal abundance and diversity in rock substrates in these seagrass beds.
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    Habitat-type and temporal comparison of the meiobenthic composition of Taklong Island National Marine Reserve
    Burgos, Lorelie A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2009-03)
    Meiofauna are very important indicators of human disturbances in the natural ecosystem. It plays a major role in the primary production, rapid nutrient cycling and other benthic chemical processes. Knowledge regarding marine benthic communities is scarce and is limited only to temperate regions. Moreover, only a few have been conducted in the Philippines, while no studies have been conducted in the Taklong Island National Marine Reserve, Nueva Valencia, Guimaras, so this serves as the baseline for further studies to be conducted in the place. This study provides a characterization of the spatial and temporal distribution of meiobenthic fauna in the Taklong Island National Marine Reserve. Specifically, the study aimed to compare the composition of meiobenthic infauna in different habitat types and to examine changes in their abundance and distribution from 4, 16 and 26 weeks after the oil spill. Meiobenthic samples were collected in Taklong Island National Marine Reserve during the Rapid and Monitoring Phases of the Benthos Project of the UPV Oil Spill Response Program. Surveys were conducted in September 2 and November 23, 2006 and February 9 2007, respectively 4, 16 and 26 weeks after the spill. Nine stations within the area were chosen based on the station grid for the biological surveys. A total of 20 taxa were identified, with nematodes being numerically dominant. It also showed the highest mean abundance in all the sampling period and for the entire habitat type. The over all mean density was (80276.71494 ind. m2, SD =19988.37), with the highest peak in February 20072007 which is 26 weeks after the oil spill (143,508.4 ind/m2). And the lowest density was recorded in the month of September 2006, 4 weeks after the oil spill (47,205.43 ind. m2). For the habitat type soft bottom has the highest recorded mean density in the entire sampling period. For the temporal variation food source, organic matter and temperature dictates the changes in distribution of meiofauna but in the study it mostly because of the oil spill happened before the sampling period.
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    Comparative growth rates and gross morphology of hybrid catfish Clarias gariepinus (female) x Clarias macrocephalus (male)
    Agase, Mark Christian A. (Division of Biological Sciences, Bachelor of Science in Biology, University of the Philippines Visayas, 2004-03)
    Catfishes are among the groups that has been considered economically important fishes in the Philippines and in other countries. The freshwater catfish Clarias macrocephalus is native to the Philippines but it is becoming scarce in many natural habitats. It is a favorite food dish due to its tender and delicious meet. Aquaculturists these days focus more their attention to the culture of exotic species like Clarias gariepinus and Clarias batrachus that in turn resulted to the near extinction of the native species. There is therefore a need to undertake a breeding program involving this native catfish and other exotic species.A 12-week study was conducted to compare the growth rates of the hybrid catfish C. macrocephalus (♂) X C. gariepinus (♀) in natural ponds and laboratory rearing conditions. In addition, the length-weight relationship was also determined. Gross morphology was also noted in the experiment.Results showed that the trend for SGR of the hybrid in natural pond and laboratory rearing conditions from weeks 2 to 12 is decreasing. Continued feeding of the hybrids on artificial diets results in poor fish growth. T-test revealed that there is a significant difference on the SGR for both the length and weight with hybrids in natural pond rearing conditions being consistently higher than the laboratory set-up.From the linear regression equation, there was no homogeneity of regression, coefficients, or slopes in the mean body lengths (MBL) and mean body weights (MBW) of me hybrids in the natural pond and laboratory rearing condition. It simply means that there is a significant difference on the growth rates of the hybrid as to the type of environment they are reared. The product-moment correlation showed that there is a linear relationship between the length and the weight of the hybrid fish, 7.9305378 X 104 being the constant. Gross morphology of the hybrids includes the appearance of a trident-shaped occipital process, which was not pointed and narrow as in the case of the parent C. gariepinus. A turtle shell-like design arranged bilaterally characterizes the dorsal side of the head. A modification of the dorsal fin was also noted as to the presence of the adipose fin at the posterior end of the dorsal fin, which was about 3-5 mm in length.