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Naujan
Lake
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Location:
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13°10'N, 121°11'E; on the northeast coast of Mindoro Island, approximately 8 km from Pinagsabangan Town, Oriental Mindoro Province. The lake is bounded by four municipalities, Naujan, Pola, Victoria and Socorro. | ||||||||
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Area:
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10,875 ha. | ||||||||
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Altitude:
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20m. | ||||||||
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Biogeographical
Province:
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4.26.12. | ||||||||
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Wetland
type:
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14. | ||||||||
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Description
of site:
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A large freshwater lake probably of volcanic origin, extending for about 14 km from north to south, and seven km from east to west. The lake is fed by local run-off and there are no major affluents; the outlet is near the north end through the Lumangbayan River. The eastern shore is precipitous, but to the west the land rises gradually and there are large areas of shallow water with an abundant growth of aquatic vegetation. There are several hot springs along the eastern shore. The maximum depth of the lake is 45m. The pH value ranges from 6.0 to 9.8, the dissolved oxygen value ranges from 7.0 to 8.0 p.p.m., and the total hardness (SBV) is 1.2. | ||||||||
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Climatic
conditions:
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Humid tropical climate with the rainfall more or less evenly distributed throughout the year (Type IV). The average annual rainfall is about 2,100 mm, and the mean monthly temperatures range from 28°C to 32°C. | ||||||||
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Principal
vegetation:
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Approximately
2,000 ha of the lake are dominated by the marsh grass Vallisneria sp
and floating mats of Eichhornia crassipes. The phytoplankton consists
of:
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Land
tenure:
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The lake and surrounding areas are under public ownership. | ||||||||
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Conservation
measures taken:
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The lake is part of the Naujan Lake National Park (21,655 ha), established in 1956. The lake is open to commercial fishing subject to the following limitations: (1) permits must be renewed annually; (2) there are bag limits for certain species not included in the list of protected species; (3) fishing is only permissible between the hours of 4.00 am and 5.00 pm; (4) no fishing is permitted in the marshy area of the lake which has been declared a fish sanctuary. Unfortunately, the enforcement of these regulations and other park regulations is reported to be extremely poor. | ||||||||
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Conservation
measures proposed:
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The Ministry of Natural Resources has expressed the desire to establish a crocodile farm and crocodile sanctuary at the lake. | ||||||||
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Land
use:
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Fishing, especially for milkfish, mullet, goby and mudfish (Chanos chanos. Mugil sp, Glossogobius giurus and Ophicephalus striazus). Other species in the catches include the tilapias Tilapia mossambica, T. nilotica, carp Cyprinus carpio, the freshwater prawn Macrobrachium sp, and the freshwater snails Ampullaria luzonica, Vivipara angularis. Where the marshes permit cultivation, the land has been drained, cleared and planted with rice. A very profitable duck-raising industry thrives in the surrounding area, along with some cultivation of fruit trees and coconuts. | ||||||||
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Possible
changes in land use:
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| Disturbances and threats: | Because of the increase in the human population in the area, the demand on the lake's natural resources has grown rapidly. Fishing is intensive and there is continuing conflict between preserving the National Park for wildlife and development of the area for commercial and subsistence level activities by the local residents. The privately owned fish corral built at the mouth of the Butas River with Government approval constitutes a major threat. Its massive door is opened during high tide and then closed, blocking the exit of marine species in their migration to the sea to breed. The small population of crocodiles, although protected by law, continues to be persecuted; fishermen catch young crocodiles on fishing lines and large animals are killed in nets. | ||||||||
| Economic and social values: | The lake is rich in nutrients and supports a major fishery of both demersal and pelagic species. Most of the inhabitants of the region depend on the lake for their livelihood. | ||||||||
| Fauna: | The rich
fish fauna includes protected species such as Mugil dussumieri, Caranx
sexfasciagus and Lutianus argentimaculojus, and harvestable species
such as Chanos chanos, Ophicephalus striatus, Glossogobius giurus,
Clarias batrachus, Tilapia mossambica and Gourami spp. The lake supports large numbers of ducks and other waterfowl. Resident species include Tachybaptus ruficollis, Ardea purpurea, Dendrocygna arcuata, Anas luzonica, Ixobrychus cinnamomeus, Butorjdes striatus, Rallus torquatus, Porzana fusca, Polioli,nnas cinereus, Amaurornis phoenicurus, Gallicrex cinerea, Gallinula chioropus, Porphyrjo porphyria pulverulentus and Sterna albifrons. Wintering waterfowl include Ixobrychus sinensis, Aythya fuligula and Fulica atra. The raptors, Haliasfur indus intermedius, Haliaeetus leucogaster, and the kingfisher Halcyon chioris collaris also occur at the lake. The Philippine Crocodile Crocodylus mindorensis, an endangered species endemic to the Philippines, formerly occurred in the area, but may now be extinct on Mindoro. The Estuarine Crocodile Crocodylus porosus still occurs in the restricted zone of the National Park. Other reptiles include the Monitor Lizard Varanus salvator. |
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| Special floral values: | No information. | ||||||||
| Research and facilities: | The Bureau of Fisheries and Aquatic Resources has a Limnological Laboratory and Experimental Fish Pond at the lake. | ||||||||
| References: | Bureau of Fisheries and Aquatic Resources (1977-1979 & 1984-1985); Karpowicz (1985); Luther & Rzoska (1971); National Environmental Protection Council (1981); Rabor (1958); Ross (1984). | ||||||||
| Criteria for inclusion: | 1b, 1c, 2a, 2b, 3b. | ||||||||
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Source:
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Haribon Foundation. | ||||||||