Agriculture, Aquatic, and Natural Resources

Spatial Distribution and Assemblages of Zooplankton during the Northeast Monsoon in Shark Fin Bay, Taytay, Palawan, Philippines

Hurriker Keen M. Malagum, Edgar P. Paalan, Noe D. Reyes, Jhonamie A. Mabuhay-Omar

Abstract

Marine Protected Areas (MPAs) are vital for biodiversity conservation, yet monitoring often focuses on larger species, neglecting microscopic organisms that form the marine food web's foundation. This research determined the spatial distribution and community assemblages of zooplankton within Shark Fin Bay. Field sampling was conducted at six stations: four within MPAs (Depla, Garden, Pinnacle, and Sandoval) and two in non–MPAs (Depla North and Macuao). Zooplankton were collected via five–minute horizontal surface tows using a 200–micron mesh plankton net. Laboratory analysis involved the displacement method to determine biomass and identification using a Bogorov counting chamber. The highest–abundance station recorded a wet weight of 49.5 ml/m³, density of 1,249.79 ind/m³, and diversity index of 1.808, while Depla North showed the lowest abundance. The Wilcoxon signed–rank test revealed no significant differences between MPA and non–MPA stations (p > 0.05). Taxonomic composition was dominated by Calanoid copepods and Cyclopoida, indicating a stable but localized community structure. Garden station was notably dominated by Appendicularia, which constitutes a significant portion of many nekton species' diet. The findings demonstrate that Shark Fin Bay supports a robust zooplankton community. This research provides critical baseline data for MPA management, suggesting that conservation efforts must account for these "invisible" foundational species to ensure long–term sustainability of the bay's fisheries and marine productivity. Further temporal studies are recommended to assess zooplankton variability in the bay.