The Philippines archipelago is blessed with panoramic landscape and bountiful natural resources. It covers ranges of mountains and floodplains to coastal area. The location in the Pacific Ring of Fire is an additional value to a fertile land with volcanoes and crater lakes. It should be noted that the most interesting part is the Laguna de Bay or Laguna Lake, the largest lake in the Philippines.
The Laguna Lake Development Authority (LLDA) is a responsible board for the management of this magnificent lake. This authority was established by law in 1969. A close cooperation between LLDA and USM researchers especially from the School of Biological Sciences were established since the formation of South East Asian Limnological Network (SEALNet) in 2016. This initiative seeks to address the collaborative insights towards addressing crucial environmental issues, and other biological field studies.The technical visit to LLDA from 4th–7th March 2019 wasled by Prof. Wan Maznah Wan Omar, while Emeritus Prof. Mashhor Mansor sponsored the students (Siti Norasikin Ismail and Mohammad Basri Eshak).
Our activity started with an informal discussion with the President of Mariano Marcos State University, Prof. Shirley C. Agrupis (Plate 1), during breakfast at Kalesa Café, Macure Hotel Ortigas. Prof. Shirley C. Agrupis was interested to establish a research networking in various fields, particularly on environmental biology and renewable energy (focusing on nipa palm (Nypa fruticans).
Plate 1: A meeting with President of Mariano Marcos State University, Prof Shirley C. Agrupis
Following that,we were accompanied by Madam Adelina Santos Borja (Department Manager of LLDA) to the main office of LLDA in Quezon City. An introduction to the researches conducted in Laguna Lake was briefly explained (Plate 2).We had a privileged to meet the General Manager of LLDA, Mr. Jaime C. Medina (Plates 3 and 4). The General Manager conveyed his support towards strengthening the collaboration and offered assistance for researchers in the SEALNet to work in Laguna Lake region and also to cover ASEAN as a whole.
Our next visit was to Institute of Biology, College of Science, University of The Philippines Diliman. We met Dr. Francis S. Magbanua (Freshwater Ecologist) and Dr. Jonathan Anticamara (Ecology and Taxonomy Research group), who later introduced us to the Director (Assoc. Prof. Dr. Ian Kendrich C. Fontanilla) and Deputy Director for Research & Extension (Assoc. Prof. Dr. Michael C. Velarde) of Institute of Biology. We had a discussion with them (Plate 5),which led to the agenda of having future collaboration between School of Biological Sciences (SBS), USM and Institute of Biology, UPD under the umbrella of SEALNet.
The next day, 6th March 2019,we had a road tour to Laguna de Bay, accompanied by Rose and Azyleah, two lady officers from LLDA.There were a few quick stops along the way. It should be noted that we passed by Marikina River, Pasig River and Manggahan flood way. These rivers were connected to Laguna Lake from West bay. The Pasig River with the length of 27 km is the only outlet of the lake flowing to Manila bay particularly during rainy season and it will backflow during dry season. During the dry season especially in April until June, salt water intrusions from Manila bay are recorded. This natural phenomenon somewhat had an effect on the ecology of Laguna Lake. Some information about Laguna Lake is shown in the Table 1 and Figure 1.
Table 1: Overview of Laguna Lake
| Total surface area | 94 800 ha (during rainy season) |
| Average depth | 2.5 m |
| Deepest point | 20 m |
| Shoreline length | 285 km |
| Inlet | Some 100 streams drain into the lake |
| Outlet | Pasig River |
| Watershed area | 2 920 km2 |
| Distinct bays | East Bay, Central bay and West bay |
| Water quality | Class C |
| Activities | Ecotourism, commercial aquaculture (common carp, milk fish, tilapia) and open fisheries |
The lake has been traditionally used as habitats for fisheries and duck-raising, waterway for minor passengers and cargo traffic, source of irrigation water in Laguna province, effluent sink by industries and municipalities, flood-control detention storage, and serves as the lower pool of the Kalayaan Pumped- Storage Hydro-Electric Plant. The local communities of the Laguna Lake are largely the Tagalog-speaking people which are predominantly Christians (majority are Roman Catholic) (Tachikawaet al., 2002). Most of the rural population are farmers (lowland and upland), and lake fishermen. The eastern bay is less productive in term of aquaculture production. Runoff from Pagsanjan River leads to severe sedimentation problem in east bay, consequently claiming large area of exposed water in Laguna Lake to become land.
As we passed by Manggahan man-made canal, we were astounded by the water hyacinth (Eichhornia crassipes) massive populations in that flood way (Plate 6). These noxious plant species are thriving well and covering most of the adjoining area.
Subsequently, water hyacinth is one of the most critical problems in Laguna Lake. Its rapid multiplication and propagation impede the water ways, hence blocking daily activities of local communities. The accumulated nitrogen and phosphate in the water ways are attributed to water hyacinth vitality (Greenfield, 2018). Source of nutrients is from anthropogenic activities such as agriculture, wastewater and livestock runoff (Plate 7).
However, there are efforts to reduce the water hyacinth population by promoting handicraft products. We visited a production house for the stems of water hyacinth utilization in Cardona, Rizal. The stems were sun dried and processed into finished products such as mats, baskets, bags, hats and wallpapers (Plate 8). Indirectly, this cottage industry supports additional income for the locals living in the municipality especially women.
This short visit had given us a glimpse of Laguna Lake, not only on the panoramic view itself but also on the ecological aspects especially the problems faced by the authority to manage this lake. We do belief that LLDA had given their best to manage Laguna Lake and the surrounding communities. There are lots of potentials to be explored in term of scientific research and international collaborations. Perhaps, a lot of information are gained and gathered during this preliminary trip.
References
Greenfield N. (2018). Paralysed by growth: A lake under siege. The UN environment. https://www.unenvironment.org/news-and-stories/story/paralysed-growth-lake-under-siege
Tachikawa Y., James R., Abdullah K. and Mohd. Desa M. N. (2002). Catalogue Of Rivers For South East Asia And The Pacific-Volume IV. The UNESCO-IHP Regional Steering Committee for Southeast Asia and the Pacific, UNESCO-IHP Publication.
-Norasikin Ismail (USM)