This IBA includes the extensive intertidal areas from the Municipality of Balanga in Bataan Province round the north and east shores of Manila Bay to Cavite City, south of Metro Manila. This large, enclosed sea bay is fringed by shallow intertidal mudflats and sand flats. Relicts of mangrove swamp survive, particularly in the Bataan area, but most have been converted to large areas of aquaculture ponds and salt pans. Plant communities in adjacent areas include coconut plantations and denuded hill vegetation. The city and port of Metro Manila is situated on the eastern side of the Bay. The site is very important for its fisheries production that supports a large urban population along the periphery of the Bay. There are high concentrations of fish traps and extensive mariculture within the open sea area, and aquaculture schemes cover about 70 km of the coastline. There is a salt pan industry at Cavite in the southeast, and several areas of shantytown development on the shores of the Bay.
Large numbers of migratory shorebirds uses the intertidal mudflats, fishponds and salt pans in Manila Bay in winter and during the migration seasons. Monthly counts at a high tide roost in Metro Manila in 1979-1982 revealed a maximum of about 32,000 shorebirds in January 1980, and in early April 1987, about 8,000 shorebirds of 20 species were recorded at seven sites, mainly drained fish ponds and areas of intertidal mudflat. It has consistently registered the highest numbers of waterbirds at any site in the Philippines during the Asian Wetland Counts in 1990-1994. There have been records of several threatened waterbirds there, but it is unclear whether this IBA is of significance for the conservation of any of these species.
BirdLife International (2021) Important Bird Areas factsheet: Manila Bay. Downloaded from http://www.birdlife.org on 02/12/2021.