Parasites are ubiquitous, infecting a diverse range of hosts including commercially important species.
Despite being commercially exploited, very few literatures on fish parasitism are published in the Philippines.
This study is one of the few conducted in a major fishing ground in the country that aims to survey the
prevalence and diversity of helminth parasites in fishes caught in the municipal waters of Orani, Bataan and
Sta. Cruz, Pampanga, Manila Bay. Fish samples from family Leiognathidae (n=86, 2 species), Mullidae (n=9,
3 species), Nemipteridae (n=13, 2 species), and Terapontidae (n=42, 2 species) were collected for dissection.
The isolated gastrointestinal tract of collected fish samples were then examined for parasites using a dissecting
microscope. Out of 150 fish samples collected, 79 samples were found to be infected with helminths. In these
infected samples, a total of 576 parasites (Acanthocephala= 312, Nematoda= 264) were isolated. Infection
rate varied among fish families with Family Leiognathidae recording the highest infection level. High intensity
of infection and dual infection were observed only in Leiognathus equulus, while other species were infected
only with either acanthocephalans or nematode parasites. Overall, acanthocephalan infection was observed
only in Family Leiognathidae, while nematode infection was observed in all fish families sampled. Interestingly
in mullids, parasitic nematode infection showed a significant positive correlation with body length (ρ=0.012).
The differential parasitic infection observed across demersal fish families sampled could be attributed to the
host’s size, feeding behavior, and parasite biology. Initial results of the study suggest wide distribution of
gastrointestinal parasites in commercially important food fishes caught in Manila Bay.