Oriental Mindoro’s ‘mine of gold’

In Photo: A man on a motorized boat passes through a flock of migratory birds preying on fish in Naujan Lake.

The Naujan Lake National Park (NLNP), a key biodiversity area (KBA) in the Philippines, is home to many species of plant and animal wildlife.

The Naujan Lake in Oriental Mindoro province and its surrounding watershed is home to unique species of fish, birds, mammals, reptiles and amphibians, making it one of the most important nature-conservation sites in the Philippines.

Director Theresa Mundita S. Lim of the Department of Environment and Natural Resource’s (DENR) Biodiversity Management Bureau (BMB) said in a phone interview last weekend the NLNP is one of the country’s important wetlands, and its protection and conservation is important to the survival of many species of migratory water birds, particularly wild ducks.

On March 27, 1956, recognizing its rich biological diversity, President Ramon Magsaysay signed Presidential Proclamation 282, making the NLNP among the first protected areas in the Philippines long before Republic Act 7586, or the National Integrated Protected Areas System (Nipas) Act of 1992, became a law.

The NLNP covers a total of 21,655 hectares, including the lake, which has a total of 8,125 hectares surface area.

It is shared by a total of 24 barangays in the towns of Naujan, Victoria, Socorro and Pola in Oriental Mindoro.

‘Mine of gold’

Naujan, the town from which the Naujan Lake was named after, used to be called “Nauhang”. The term was coined even before the arrival of foreigners on the island of Mindoro.

To the Spaniards, Naujan is the island of Mina de Oro, or “mine of gold”, while to some Chinese scholars it is Ma-I (country north of Borneo) and Min-to-lang (important port along the coast), according to a profile of NLNP prepared by the DENR-BMB.

According to local legends, Naujan got the name from the words “nauhaw si Juan”, or literally “Juan was thirsty.”

While the description “mine of gold” refers to the yellow metal, the lake, its watershed and the bounty of the entire ecosystem can also be considered as economically important, like gold, as it provides of sources of food, water and livelihood for centuries.

Unique wetland

The country’s fifth-largest lake, the Naujan Lake has a surface area of 8,125 hectares, rising 20 meters above sea level with a maximum depth of 45 meters.

The DENR-BMB reported that its watershed, which covers about 30,000 hectares, is drained by the Macatoc, Borbocolon, Malayas, Malabo, Maambog, Malbog and Cusay Creek in the East, by Bambang, Tigbao and Tagbakin Creek in the West, Subaan and Singulan River in the South.

Because of its Type III climatic condition, which has no pronounced maximum rain period and with a short dry season lasting from two to three months, the lake provides adequate water ideal for agriculture.

On the other hand, the water of the lake drains via its lone outlet, the Butas River flowing toward Tablas Strait with an outlet at Barangay Lumang-bayan in Naujan at the north of the NLNP.

Underscoring the importance of maintaining wetland ecosystems healthy, Lim said that, besides providing water for domestic use and irrigation, and food, like freshwater fish, lakes are also important in providing communities with natural defense against climate change’s worst impacts.

“Wetlands, like lakes, marshes and, most especially, peats, help prevent flashfloods and can mitigate climate-change effects, like sea-level rise and flood brought about by storm surge,” Lim told the BusinessMirror over the phone.

Biogeographic zone

The NLNP is one of the major biogeographic zones of the Philippines. Experts describe it as a unique wetland because it harbors numerous unique flora and fauna in various habitats—from terrestrial, freshwater and coastal to marine ecosystem.

It hosts several island endemic species that are found only in Mindoro and nowhere else in the world.

Besides its land cover, the type of water in the lake—a permanent freshwater, which is very rare—is one of the peculiar characteristics of NLNP.

Another prominent land cover in NLNP is marshland, which measures about 585 hectares, or 3 percent of NLNP and a portion of it is peatland.

In such habitat, all 16 species of migratory birds recorded in the park are found, including the threatened Philippine duck.

Ramsar site

Being an important staging ground for migratory birds, the NLNP has been declared a Wetland of International Importance under the Ramsar Convention on November 12, 1999. There are seven listed Ramsar sites in the Philippines.

The other six Ramsar sites are the Las Piñas-Parañaque Critical Habitat and Ecotourism Area along Manila Bay; the Puerto Princesa Subterrenean River National Park in Puerto Princesa City, Palawan; Tubbataha Reefs Natural Park also in Palawan; Olongapo Island Wildlife Sanctuary in Olongapo City; Agusan Marsh Wildlife Sanctuary in Agusan provinces; and the Negros Occidental Coastal Wetlands Conservation Area in Negros Occidental.

The NLNP is also recognized as an Anatidae Site of the East Asian-Australasian Flyway Network mainly because of the huge number of migratory birds, particularly wild ducks, visiting the lake during migration season.

Ecosystem functions

Like most inland wetlands, which include river systems, lakes, marshes and peats, Naujan Lake performs important ecosystem services, including serving fisheries, irrigation, transportation and water for domestic uses.

While only 15 percent of the total area of the park is classified as forestland, its vegetation is impressive.

It is covered with a mixture of forests, shrubs and grassland with 443 indigenous and 74 exotic species, many of which are threatened or potentially endangered.

The swamps and marshes within the NLNP, which include peat land, also perform valuable ecological functions, including serving as silt and pollution traps, while the presence of varied wildlife and the lake’s aesthetic and recreational value adds to its potential for ecotourism.

Biodiversity

According to the DENR-BMB, terrestrial and aquatic wildlife thrive in the NLNP.

A total of 105 species of birds, 21 species of mammals and 33 species of reptiles and amphibians were recorded in the NLNP.

These include the endemic and threatened Philippine duck and the globally significant population of tufted ducks, as well as other migratory water birds, such as terns, herons, egrets, bitterns and stilts.

Endemic and threatened birds, such as the Mindoro imperial pigeon, Mindoro bleeding-heart pigeon, black-hooded coucal and Mindoro hornbill, are also found in the area.

The endemic Philippine freshwater crocodile was also discovered in the NLNP.

Native, migratory fish

The Naujan Lake is known for having good number of native fish, including the endemic goby fish, or biya.

According to the DENR-BMB, a total of 30 fish species have been recorded in the lake. Also, 11 migratory fish species have been recorded in Naujan Lake in 2011, making it an important breeding ground, nursing and feeding ground, for migratory fish, as well.

Meanwhile, 18 of the fish species recorded in NLNP are species of economic importance. Two of these species are classified as globally threatened, the pait (vulnerable) and common sawfish, also known as barakan or pakangan (critically endangered) in Bicol on the Red List of Threatened Species of the International Union for Conservation of Nature (IUCN).

The majority of the fish species recorded in Naujan Lake were migratory species living primarily in marine environment but frequently visit freshwater ecosystems through the Butas River and stay, but return to the sea when they become sexually mature.

According to the Information Sheet on Ramsar Wetlands provided by the DENR-BMB, some species just enter freshwater in pursuit of possible prey, and leave afterward.

“In this process, Butas River serves as corridor connecting a marine environment and the freshwater ecosystem of Naujan Lake. Also, it is the only outlet of the lake toward the sea,” the information sheet stated.

Moreover, at least three elasmobranch species, such as sharks and rays, have been recorded in Naujan Lake and Butas River. These incude two near-threatened species—the bull shark and black-tip reef shark.

Salmons are known to migrate from the ocean to breed in freshwater, traveling against raging rivers to reach the lakes.

In the Philippines certain fish species, like the ludong—or lobbed river mullet breeds or “President’s fish”—also migrate to feed, if not breed, in rivers and lakes. It also breeds in the ocean.

This fish species migrate through rivers, particularly in Cagayan River, and lakes during certain stage of its life cycle before they become mature to breed in the ocean.

The talakitok, a marine-water fish, breeds in brackish water, usually the mouth of a river. When it finds it way to Taal Lake through the Pansipit River, they grow and become maliputo, Lim said.

Off-limits to aquaculture

Ricardo Natividad, a forester and the protected area superintendent of the NLNP, said the Naujan Lake is under a strict management regime. He told the BusinessMirror in a phone interview last weekend that, unlike other lakes in the country, the Protected Area Management Board (PAMB) wants to keep the lake healthy, even against invasive alien fish species, like tilapia and bangus (milkfish).

“There are no fish cages in Naujan Lake. Fish-cage operation is prohibited because we don’t want tilapia and bangus affecting our native fishes in the lake,” Natividad said in Filipino.

He said because of this, they are able to maintain a healthy population of native fish in the lake.

“Unlike in Laguna de Bay and Taal Lake, we do not allow aquaculture because it will threaten the population of native fish,” Natividad said.

Shrimps and crabs can also be found in Naujan Lake, along with native fish, like gourami, mudfish, white goby and common carp.

Bangus and tilapia have been known to occur in Naujan Lake but the population is not alarming, unlike in areas where fish-cage operation is allowed.

“We also strictly prohibit the release of exotic fish in the lake because we don’t want to have a problem like Laguna de Bay and Taal Lake,” he said.

Healthy but threatened

Joy Navarro, Ecosystem Management Specialist of the DENR-BMB’s Caves, Wetlands and Other Ecosystems Division, said over last weekend in a phone interview the Naujan Lake is relatively healthy, with native fish species still thriving in the area.

She told the BusinessMirror this is mainly because of the strong management regime put in place by the PAMB and implemented by the Office of the Protected Area Superintendent.

“Many migratory birds stay at the Naujan Lake because they found the area to have a healthy environment. Wild ducks, for instance, go there because there are plenty of food to feed on,” Natividad said.

However, she said like most lakes, the Naujan Lakes remain vulnerable to various threats. A serious threat to the lake is the increasing population of people living around it.

Natividad said most of the people living in the area are farmers, and the use of pesticide and fertilizers are sure to find their way to the lake.

She said there are reports that fish catch in the area is dwindling, prompting some residents to clamor to the Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR) to introduce tilapia in the lake.

“We are opposing this because it will surely have adverse impact to native fish species,” Navarro said, citing the case of the Laguna de Bay and Taal Lake, where native fish species are threatened by tilapia and other invasive alien fish species. According to Navarro, the people living around Naujan Lake need livelihood support to reduce their overdependence on the lake’s bounty.

Management plan

Recognizing the importance of protecting and conserving the Naujan Lake, the Mindoro Biodiversity Conservation Foundation Inc. and the DENR Occidental Mindoro, Oriental Mindoro, Marinduque, Romblon and Palawan jointly facilitated the development of a 10-year management plan for the entire NLNP.

The Naujan Lake National Park Management Plan 2014-2024’s vision for NLNP carries four major elements: (a) peaceful and abundant lake and its environs; (b) effective management system in place; (c) biological diversity is given importance; and (d) communities enjoy a sustainable and progressive way of life.

Among its objectives is to ensure that the NLNP’s aquatic and terrestrial resources and environment are conserved to provide long-term benefits from sustainable use of natural resources and ecosystem services to communities and other stakeholders.

The plan, including strategies, are now in place. The next step is to implement it and make sure that the lake and its bounty, like a real “mine of gold” will continue to provide for people and wildlife alike.

Image Credits: Alain Pascua