While the 10-million-year-old Lake Lanao remains "pristine and clean,” the  local government units around the area have to step up efforts to conserve and protect the ancient lake from degradation according to the study conducted by the Department of Science and Technology-National Research Council of the Philippines (DOST-NRCP).

The results of the three-year study was presented by Dr. Fema M. Abamo, a professor of Mindanao State University in Marawi City, during a webinar presentation for the regional basic research caravan for Bicol.

“Our Lake Lanao from all sampling sites is still pristine; our water is still clean,” she said.

For two years, Abamo’s team monitored the water quality of Lake Lanao in five sampling sites. These included Marawi City, Ramain, Balindong, Taraka, and Binidayan.

The researchers used the abundance of one-celled protozoan ciliates as bio-indicators of organic pollution to monitor the site.

The highest ciliate abundance was observed in the littoral zone of Balindong at 0.0061cells/mL during the dry season, they noted.

Abamo’s group cited a previous study in 1989, which categorized lakes as ultra-oligotrophic when their ciliate abundance is equal to or lower than 2.4cells/mL.

"Lake Lanao, therefore, is ultra-oligotrophic having ciliate abundance below the set range in all sampling sites. Such lake category has very low nutrients, scarce growth of plants and algae, and high dissolved oxygen indicative of a clean, healthy, good water quality and not organically polluted lake,” they said.

The researchers got their water samples from 50 to 100 meters away from the lakeshore in the shallower littoral zone and towards the deeper open water in the pelagic zone.

The DOST noted that the results of the team’s study were affirmed by another group in the same program conducting the physical and chemical characterization of the lake. They found the same findings that the lake is not polluted but still healthy and has good water quality,

The DOST-NCRP study was temporarily suspended and eventually allowed to resume after the 2017 Marawi siege.

“The lake was reportedly deteriorating due to increased human population and activities around the lake,” Abamo said.

Her team proposed that since people have resettled back near the lake after the Marawi siege, the local governments which have jurisdiction over the area should strengthen their policies to maintain the healthy condition of the lake.

“We have recommended to the local government to create and implement stricter policies and ordinances to conserve the lake, and regulate and check both the residential and business establishments around the lake,” said Abamo, a member of DOST-NRCP’s 4,944 research pool involved in various scientific disciplines.

The DOST cited that Lake Lanao is listed as one of the 17 ancient lakes of the world with a tectonic-volcanic origin.

It is the second largest lake in the Philippines and the largest one in Mindanao, home to 18 endemic cyprinids or freshwater fishes related to the carps and minnows that are found nowhere else in the world, it said.

"For generations, Lanao Lake has been a potent natural resource that breathes life to the Maranaws, as a source of their food and water, livelihood, religious practices, transportation and sports. But more than anything, the lake has shaped the Maranaw culture and tradition to what it is now and it has become imperative for the Maranaws to preserve its pristine beauty for a better and sustainable future,” it said.