Differences in size structure of genus porites in two locations in the Philippines

Date of Publication


Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology

Subject Categories



College of Science



Thesis Adviser

Wilfredo Roehl Y. Licuanan

Defense Panel Chair

Mary Jane C. Flores


Slow growing massive Porites corals are necessary framework-building elements of the reef ecosystems in the Philippines. Constant change of the earth climate and ocean, with the addition of local threats from human activities, natural calamities, predator outbreaks and coral diseases, constantly hinders and slows down its growth. Since the research on this subject matter is rarely conducted in the Philippines, the purpose of this study is to determine the size structure of Porites corals in two locations in the Philippines that will serve as a baseline study for the four stations and identify the significant factors that can affect its growth. In this study, Porites corals in station CR4A and CR4B of El Nido, Palawan and stations SP158 and SP159 of Biri, Northern Samar were classified into six different size classes. Size class 4 of station CR4B had the highest number of Porites (n=625) while size class 6 in station SP159 had the lowest (n=1). Size class 1 and size class 2, which create smaller Porites corals, have the highest relative frequency of 60% in station SP159. Furthermore, size class 5 and size class 6 have the highest relative frequency located at Station 158 at 15%. A chi-square test was utilized to determine if there is a statistically significant difference in the size structure of Porites corals accounted in each station. Results show that the number of Porites corals per size class in Station 159 was significantly different from stations CR4A (p=0.006) and SP159 (p=0.042). High water turbidity and sedimentation, as well as destructive fishing, are factors that can affect the differences in the growth of Porites coral in station SP159. Pooled number of corals per size class in each station revealed a significant difference in size structure between El Nido and Biri (p=0.010). This may be because stress-factors related to climate change, bleaching events, typhoons and local treats that repeatedly halts and hinders the regrowth the of Porites corals.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall

Physical Description

1 computer disc 4 3/4 in.


Porites; Reefs--Philippines--Biri; Northern Samar; Reefs--Philippines--El Nido; Palawan; Biotic communities--Philippines; Ecology--Philippines; Ecosystem management--Philippines

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