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Undergraduate Special Problem

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

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Committee Chair: search.filters.chair.Padilla, Philip IanDegree: search.filters.degree.Bachelor of Science in Biology

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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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    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.