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UPV Theses and Dissertations

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Committee Chair: search.filters.chair.Tayo, Gilma T.Keyword: search.filters.keyword.Aquaculture

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    Comparative development of larval performance of catfish hybrids (Clarias macrocephalus Gunther x Clarias gariepinus Burchell)
    Cabanos, Cerrone Salamat (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-03)
    Our native catfish, Clarias macrocephalus, is one of the most well-accepted fish in the country. With its soft and savory flesh, this species has high demand in local markets. However, due to its relatively slow growth and poor breeding activity, our native catfish has become rarely used nowadays in aquaculture. This led to the introduction of exotic and faster growing species like the African catfish, Clarias gariepinus, and Thai catfish, Clarias batrachus, which in turn, resulted to the near extinction of the native species. There is therefore a perceived need to undertake a breeding program involving this native catfish and other exotic species. One potential solution to increase our production rate of the native catfish is to hybridize it with the African catfish. Interspecific hybridization has been a popular breeding program utilized by researchers attempting to produce fish expressing hybrid vigor (positive heterosis) or for combining valuable traits from more than one species. This study is on the characterization of the early developmental stages of fertilized eggs and the comparison of larval performance (in terms of percent fertilization, hatching and larval survival) resulting from the artificial cross of Clarias macrocephalus (native catfish) and Clarias gariepinus (African catfish) and its parental species. In comparing the rates of egg development among crosses (all macrolecithal and discoidal cleavage), it was determined that fertilized eggs of the standard hybrid cross (C. gariepinus male x C. macrocephalus female) have a relatively faster rate of development than those from the reciprocal cross (C. macrocephalus male x C. gariepinus female). Results on determination of larval performance showed that there is no significant difference in percent fertilization and percent survival after 7 days between hybrid and parental crosses. However, in terms of percent hatching, the reciprocal hybrid cross (C macrocephalus male x C. gariepinus female), together with the C. gariepinus x C. gariepinus parental cross had a significantly higher percent hatching (P < 0.01) compared to the standard cross (C. gariepinus male x C. macrocephalus female).
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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.
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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.