The Guinayangan Republic

A protected gulf area with an estuary in the northern part created by drainage from the mountains of the northern Bicol region (Mount Labo). The coast is largely intact mangrove with intertidal mudflats, particularly in protected bays such as Pens Bay. Some areas have been converted to aquaculture ponds, and there are some coral reefs offshore. The Gulf is saline with some dilution from the three main river sources to the north. The average tidal variation is about l.25m.

Humid tropical climate with the rainfall more or less evenly distributed throughout the year

The aquatic vegetation includes mangroves in the intertidal zone, the principal species being Rhizophora apiculata, Sonneratia alba and Ceriops tagal. Other species include Schyphiflora hydrophyllacea, Avicennia marina, Nypa fruticans, Excoecaria agallocha, Acanthus spp, Instia retusa, Lumnitzera sp, Bruguiera gymnorhiza, B. parviflora, B. cylindrica and lylocarpus granatum. The vegetation on the adjacent degraded hillsides is dominated by Pandanus spp and Cocos nucifera.





Howes proposes the management of suitable areas (particularly near Guinayangan and Buenavista) for mangrove replanting schemes, and the strict application of the Bureau of Forest Development's guidelines for aquaculture development in the conversion of further areas to fish ponds. Further study of waterfowl migration within the Gulf is required.

The principal activity is fishing, and there are important local fisheries in the vicinity of all mangrove areas. Mangroves are harvested for timber and other products, and mangrove forest has been converted to aquaculture ponds in Guinayangan and Buenavista. The principal land use in the adjacent uplands is agriculture, mainly the cultivation of Cocos nucifera and maize.



About 15 hectares of mangrove at Guinayangan have been surveyed for conversion to aquaculture ponds, and some clearance has already been implemented.


The conversion of mangrove forest at Guinayangan to aquaculture ponds is a major threat. Many fish ponds along the seaward edge have been eroded by wave action and abandoned. A scheme to dam the upper section of the Gulf from Catimo to Guinayangan for use as a large-scale aquaculture project has failed. The continued denudation of the remaining forested patches in the water catchment area is causing increased soil erosion and this is resulting in increased siltation in the coastal wetlands.


The fisheries are of considerable local importance in this agriculturally very poor region. The mangrove forest provides a natural barrier against coastal erosion. The Gulf is important for scientific research as it constitutes one of the few sites in Luzon with large areas of mangrove forest still in a healthy condition.

An important area for migratory Ardeidae and shorebirds. Some 400 shorebirds of 18 species were observed at two sites in mid-May 1987, but the area undoubtedly holds many more birds during the peak migration seasons. More importantly, the area was found to hold a total of 41 Chinese Egrets Egretta eulophotes as well as lesser numbers of E. garzetta, E. alba and Ardea purpurea.
There is a very rich zoobenthic biomass evident in the intertidal mudflats.
The area supports some of the largest tracts of diverse mangrove forest in Luzon.





The Forest Research Institute and Asian Wetland Bureau conducted a preliminary wetland evaluation and shorebird survey in April 1987

Most of the Photos are Courtesy of Rastamarie's Flickr
Excerpt from www.arcbc.org.ph