Community composition of polychaetes in Manila South Harbor

Abstract

Manila Bay is a natural harbor situated south-west of Luzon, bordered by the provinces of Bataan, Pampanga, Bulacan, Metropolitan Manila, and Cavite. The bay serves as one of the main gateways to the Philippines and houses the Port of Manila, one of the largest and busiest ports in the country. International shipments are facilitated through its South Harbor section. With the international shipping vessels carrying macrofoulers onto their hull surfaces, accidental introduction of non-indigenous organisms could threaten the native ecosystem. Among the macrofoulers that have been documented in the ecosystem of the Manila Bay, polychaetes are considered to bear importance as they could be used as indicators of environmental conditions particularly the marine water quality. This study documents the polychaete community composition in the Manila South Harbor and classifies the identified polychaete families into indigenous and non-indigenous taxa. Five PICES fouling collectors were deployed on each of five designated sampling sites in the man-made marina of the Manila Ocean Park, each being submerged one meter below the minimum sea level as per the National Mapping and Resource Information Authority (NAMRIA) records. Specimen collections along with other macrofouling organisms were done every four weeks. Physicochemical parameters were also recorded along the five sampling sites every two weeks. After the 122-day study period, a total of 4510 individuals from six phyla and 15 distinct marine invertebrate families were documented. Seven families of polychaetes were identified, all of which are classified as indigenous to the Philippine waters: Serpulidae, Hesionidae, Nereididae, Polynoidae, Phyllodocidae, Dorvilleidae, and Spionidae. However, member-species of Serpulidae, which were narrowed down as the invasive tube worm Hydroides elegans, was documented as a non-indigenous polychaete. It is recommended that a consistent documentation of macrofoulers in Manila South Harbor be done and this study be considered as one of the references for the creation of guidelines concerning the Manila Bay conservation efforts.