Philippine Science Letters
vol. 6 | no. 1 | 2013
published online February 21, 2013


Initial assessment of parasite load in Clarias batrachus, Glossogobius giuris and Oreochromis niloticus in Lake Taal (Philippines)

by Gil Cauyan1, 2, Jonathan Carlo Briones3*, Eugene De Leon1, Julio Arsenio Gonong1, Eduardo Omar Pasumbal1, Ma. Czarina Isabel Pelayo1, Manuel Anthony Piņera1, Rey Donne Papa1,2

1Department of Biological Sciences, College of Science, University of Santo Tomas,
 Manila, Philippines
2Research Center for the Natural and Applied Sciences, University of Santo Tomas,
 Manila, Philippines
3Graduate School, University of Santo Tomas, Manila, Philippines



Fish parasites are ecologically important because they shape community and ecosystem structure by influencing trophic interactions, host fitness, and food webs. We surveyed fish parasitofauna from Lake Taal and provided initial quantitative and qualitative measures of parasite burden. This was then correlated with fish size, as a preliminary attempt to relate parasitism with fish overall fitness. A total of 60 specimens of Oreochromis niloticus, Glossogobius giuris and Clarias batrachus were collected from the lake in June, October and November 2010. From these, five taxa of digenetic trematodes (Opegaster sp., Erilepturus sp., Euclinostomum sp., Orientocreadium sp., and Clinostomum sp.) and one parasitic cyclopoid (Lernaea sp.) were collected and identified. Results revealed that the most prevalent parasites, in both occurrence and number, were Opegaster sp. in G. giuris and C. batrachus, and Lernaea sp. in O. niloticus. C. batrachus was the most burdened as it harbored parasites in most of its internal organs. Linear correlations reveal negative trends between parasite burden and fish size for all fish species analyzed, suggesting that smaller fish tend to harbor more parasites than larger fish. However, this relationship was not found to be statistically significant (p>0.05). Nevertheless, these results reveal the challenges that many researchers will face in their effort to understand the implications of parasitism to both caged and feral fish, in relation to natural and anthropogenic factors. Moreover, it highlights the need for more ecological studies on parasitism in the Philippines, if we are to improve fish conditions in both open waters and caged areas not only in Lake Taal, but also in all Philippine lakes, especially those that are being utilized for aquaculture.

* Corresponding author
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Received: May 14, 2012
Revised: January 4, 2013
Accepted: January 6, 2013
Published: February 21, 2013
Editor-in-charge: Eduardo A. Padlan