Distribution of free-living nematodes in a tidal flat of Banate Bay, Iloilo, Philippines


by: Kris Angeli S. Sanchez, Wilfredo L. Campos, and Annabelle G.C. del Norte-Campos, Joey Genevieve


Meiobenthos samples and related environmental parameters were examined along a transect with six stations extending 4 km from the shoreline in Banate Bay, Iloilo, Philippines in April (dry), July (onset of SW monsoon rain) and October (end of rainy season) in 2014. Free-living nematodes constituted 90% of the total meiofauna and showed a mean density of 51.4 ind. cm-2. A total of 89 nematode genera from 23 families were identified, with Paracomesoma, Viscosia, Daptonema, Paramonohystera, and Cyatholaimus as the top five genera (35.6% of overall frequency). Nematode densities (ln-transformed) showed significant differences (p=0.03) temporally but not spatially. Higher densities were observed during the rainy season than dry season. A stepwise multiple linear regression analysis indicated that nematode density was negatively correlated with bottom salinity, while genus richness was negatively correlated with surface turbidity and bottom salinity. The nematode assemblage was dominated by epigrowth feeders, with a shift to non-selective deposit feeders as sediment organic matter had accumulated in October.

Keywords: OceanBio and Marine Bio Laboratories