menu.header.image.unacom.logo
 

National Committee on Marine Sciences (NCMS)

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6

Browse

Filters

2014 - 201912020 - 20231

Settings

Ocean Decade Challenge: search.filters.odc.Challenge 1: Understand and beat marine pollutionUNESCO Keyword: search.filters.subject.Aquaculture

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Feeding and reproductive phenotypic traits of the sea urchin Tripneustes gratilla in seagrass beds impacted by eutrophication
    Bangi, Helen Grace P.; Juinio-Meñez, Marie Antonette (MDPI AG, 2023-07-11)
    The sea urchin Tripneustes gratilla is a major grazer and is, hence, an excellent key model organism to study to gain a better understanding of responses to changes in its habitat. We investigated whether there are significant variations in the feeding and reproductive phenotypic traits of populations from three seagrass bed sites, with respect to their proximity to fish farms in Bolinao, northwestern Philippines. We established three stations in each of the three sites: the far, the intermediate, and those near the fish farms, and compared the sea urchins’ phenotypic traits and determined whether these were related to seagrass productivity and water parameters. Regardless of the sampling period, adult sea urchins (66.92 ± 0.27 mm test diameter, TD, n = 157) from the areas intermediate and near to the fish farms had significantly lower indices of Aristotle’s lantern, gut contents, gut and gonads, and lower gonad quality (high percentage of unusual black gonads), compared to those from the far stations. Multivariate analysis showed that the smaller feeding structures and gut, lower consumption rates and lower gonad indices and quality of sea urchins in the intermediate and near fish farms were positively related to lower shoot density, leaf production and species diversity, as well as lower water movement in those stations. The larger size of the Aristotle’s lantern in the far stations was not related to food limitations. More importantly, the phenotypic variability in the feeding structures and gonads of sea urchins in the same seagrass bed provides new evidence regarding the sensitivity of this species to environmental factors that may affect variability in food quality.
  • Thumbnail Image
    17-year change in species composition of mixed seagrass beds around Santiago Island, Bolinao, the northwestern Philippines
    Tanaka, Yoshiyuki; Go, Gay Amabelle; Watanabe, Atsushi; Miyajima, Toshihiro; Nakaoka, Masahiro; Uy, Wilfredo H.; Nadaoka, Kazuo; Watanabe, Shuichi; Fortes, Miguel D. (Elsevier, 2014)
    Effects of fish culture can alter the adjacent ecosystems. This study compared seagrass species compositions in 2012 with those in 1995, when fish culture was less intensive compared to 2012 in the region. Observations were conducted at the same four sites around Santiago Island, Bolinao: (1) Silaqui Island, (2) Binaballian Loob, (3) Pislatan and (4) Santa Barbara, and by using the same methods as those of Bach et al. (1998). These sites were originally selected along a siltation gradient, ranging from Site 1, the most pristine, to Site 4, a heavily silted site. By 2012, fish culture had expanded around Sites 2, 3 and 4, where chlorophyll a (Chl a) was greater in 2012 than in 1995 by one order of magnitude. Enhalus acoroides and Cymodocea serrulata, which were recorded in 1995, were no longer present at Site 4, where both siltation and nutrient load are heavy.