An Ecological Assessment of Seaweed Communities in Masinloc, Zambales

Abstract

The study focused on three seaweed communities in Masinloc Bay, Masinloc, Zambales, to include abundance, distribution and diversity of seaweed species. Their corresponding associated flora and fauna and the prevailing water quality (physico-chemical) aspects were also noted. Survey of seaweed species revealed a total of forty-one (41) species, registering a highest total seaweed density of 25 individuals/m2, highest Simpson's index of diversity at 13.862, highest Shannon's index of Equitability value of 0.613 and highest total biomass of 444.89 g/m2. Seven (7) species were found to be economically important. Compared to other similar studies conducted, Masinloc bay has relatively low biomass and diversity. Associated flora and fauna included seagrasses (Enhalus acoroides, Thalassia hemprichii), macrograzers (starfish, sea urchins, siganids) and jellyfish. All sites had an average temperature of 30.25°C, salinity averaged at 34.26 ppt, average water movement of 0.148 m/s, average limit of visibility at 12.18 m, average dissolved oxygen at 5.1 g/ml and an average pH level of 7.27 Possible factors identified to have affected the diversity of seaweed species included high temperature levels exceeding the optimal range for growth (15-30°C) and proximal to the upper limit for survival of tropical seaweeds (30-35°C). Grazers may have also controlled the proliferation of seaweed species. The sandy-muddy substrate may have also imposed an adaptation requirement for survival that resulted in the low diversity observed.