Phytoplankton sampling was done in Agutayan Island , Jampason, Jasaan, Misamis Oriental from August to November 2006 at 6:00 ? 8:00 a.m. using horizontal hauling. A total of sixty-four (64) species were observed and identified of which four (4) species are under Kingdom Monera (4 blue-green algae, Phylum Cyanophyta) and sixty (60) species are under Kingdom Protista of which there is one species of green alga (Phylum Chlorophyta), thirty-one (31) centric diatoms and ten (10) pennate diatoms (Phylum Bacillariophyta) and eighteen (18) dinoflagellates (Phylum Protozoa).
Agutayan Island phytoplankton had an average cell density of 383 cells/L and it was densest in August with 732 cells/L, denser in October with 383 cells/L and least dense in November with 32 cells/L. Compared by stations, offshore was denser with 901 cells/L than reef edge with 605 cells/L. Diatoms (Phylum Bacillariophyta) showed the highest cell density of 239 cells/L (72.30%), followed by blue-green algae (Phylum Cyanophyta) of 141 cells/L (25.56%) dinoflagellates with a cell density of 2 cells/L (2.43%) and lastly by green alga with 0.07 cell/L (0.01%) which was only observed in August.
Physico-chemical parameters obtained were current velocity, water transparency, temperature, salinity and pH level. Pearson Correlation Coefficient revealed moderate negative correlation of current velocity, water transparency and temperature with cell density. However, salinity yields slightly positive correlation while pH level was not correlated because of inaccuracies of readings. Tested for significance, the three physico-chemical namely current velocity, water transparency & temperature yields to significant results while salinity did not. Compared by stations, the abundance of phytoplankton didn't conform to the obtained results in Pearson.
Shannon ? Weiner Diversity Index was used for species diversity and yield to 2.45 with
an Hmax of 4.15 in Agutayan Island .