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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/30

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    Abundance and composition of the gut contents of orbiculate cardinal fish, Sphaeramia orbicularis (Apogonidae) in Palompon, Leyte
    Canda, Danielle Clare C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    The study was conducted to examine the gut contents of Sphaeramia orbicularis using specimens from catches of a sled trawl survey conducted from June 2011 to May 2012 in Palompon, Leyte. One hundred seventy-one fish specimens were categorized into six different size classes maintaining an interval of 1 cm: 1-1.9 cm, 2-2.9 cm, 3-3.9 cm, 4-4.9 cm, 5-5.9 cm, and 6-6.9 cm. The guts of the fish specimens were isolated and the contents were placed on a petri dish for identification and counting. Based on the observed percentages of chyme, the species consume a large amount of easily digested materials. The increasing number of prey items as size class increases revealed that the smaller fishes prey on smaller organisms while the larger ones prey on the larger counterpart, and thus smaller predators are a subset of larger predators. Apogonids displayed a generalist diet, consisting mostly of demersal plankton and benthic invertebrates.
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    Filtration rate of the marine clam, Kaltelysia sp. at different light intensities and fed with microalgae Isochrysis galbana and Chaetoceros calcitrans
    Bravo, Agnes Therese A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2005-04)
    Filtration rate of the marine clam, Katelysia with body lengths ranging from 5-6 cm and body weight from 45-65 g were determined by using the indirect method of suspension depletion and monitored by direct algal cell count. The effects of light intensity and algal species on the feeding behavior of the clam were determined. The first treatment involves total darkness where the basins containing the clams were covered with black plastic bag. In the second treatment, the basins with the clams were placed under ordinary light condition (12h light; 12h dark) and in the third treatment, the basins with the clams were positioned under a 20-watt bulb with continuous illumination (24h light). Results showed significant differences in the filtration rates of clams in different light intensities. It showed higher filtration rate in the total darkness treatment (F=0.132555907) followed by the 12h light: 12h dark treatment and lowest at the treatment provided with 24 h illumination. Apparently, illumination affected valve opening and siphon extension of the clam which also affected the filtration rate of Katelysia. Under total darkness treatment, the clams opened their valves and extended their siphons. Hence, there was highest ingestion of algae or filtration in total darkness which showed to be the optimum condition to stimulate or promote feeding. In the algal species preference experiment, the food used were either Isochrysis galbana, Chaetoceros calcitrans , or a mixture of both. Results showed that I. galbana had the highest number of cells ingested by the clams and removed from suspension. This is considered to be the preferred algal species (F=0.119713) followed by a mixture of both, and lowest on the treatment where C. calcitrans was used as food. The preference of the clam on Isochrysis galbana over Chaetoceros calcitrans could be its smaller size based on dry weight.
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    A comparison of the gut contents of two Cardinal Fish, Fowleria vaiulae (Jordan & Seale 1906) and Fowleria variegata (Valenciennes 1832) in seagrass beds of Palompon, Leyte
    Biantan, Lindsay S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Seagrass ecosystems support much of the Philippines’ coastal marine resources with the presence of a rich diversity of species, including the economically important ones. Understanding the diet composition of fishes through gut content analysis is essential for selecting species for aquaculture. Specimens of Fowleria vaiulae and Fowleria variegata were obtained through a trawl survey in the seagrass beds of Palompon, Leyte from November 2011 to February 2012. A total of 291 guts were analysed in this study. Results showed diet composition of both species is mostly made up of benthic invertebrates. A high percentage of chyme was observed in both species (46-65%), suggesting the consumption of easily digested materials. Also for both Fowleria species, it was observed that smaller size classes consume a higher number of small preys while larger size classes feed on larger preys. Small invertebrates such as tanaids and amphipods were more abundant in the guts of F. vaiulae and large preys of shrimps and crabs dominate the diet of F. variegata. This difference may be due to food partitioning in co-occurring species to avoid competition.