“Mabaho na talaga sya” he further says, the water is low quality and the oxygen level is low. So when strong winds blow over the lake due to the southwest monsoon or amihan it will cause big waves that will soon cause upwelling, the water from the bottom with low oxygen level will rise.
With an area of 18 square kilometers and has an average depth of 8 meters, the Lake Buhi found in the town of Buhi, Camarines Sur in Bicol amid the effort of the Bureau of Fisheries and Aquatic Resources (BFAR), the Local Government Unit and some non-governmental organizations, it is still in a high risk of totally dying out.
The municipality of Buhi, under the virtue of Proclamation No 573 on June 6, 1996, declared it as a watershed and forest reserve. In 2006, according to the ASEAN, Regional Center for Biodiversity Conservation (ARCBC), the lake covers 1,707 hectare out of the original 1,800 hectare measures 6.8-12.0m deep.
The lake generates 15 tons of fish especially tilapia a day, the average production of fish per cage is 1,000 kilos. An estimated 5,475 tons of tilapia is being harvested every year. While the fishing season is whole year-round.
Aside from sinarapan, the lake also serves as home to seven other native fish species, five of which are endemic, and the surrounding forest is home to at least 25 bird species, five of which are endemic.
Apart from being a haven to its rich biodiversity, it also powers a hydroelectric plant that generates about 2.8 megawatts that contribute in sustaining the power requirements of Luzon, and irrigating at least 12,000 hectare of farmlands in the RINCONADA area including Iriga City and the Municipality of Pili.
Lake Buhi is converging tributaries, and it also serves as a major watershed for the entire municipality. And above all, the lake serves as the main livelihood sources of the surrounding barangays.
Hierarchy System and Usage
The NIA again construct hydraulic control structure at the mouth of the Tabao River to impound more water in the lake for irrigation. These facilities prevented not only several migratory fish species from entering the lake but also some of the indigenous fish species from moving to their respective spawning grounds along the Tabao-Buhi Rivers.
The lake system is delineated into five zones: southeast, northeast, northwest, southwest and a central water zone. (See Figure 1.)
In the conducted zonification, the central water zone is assumed to be the deepest portion of the lake, while the eastern side is shallower than the western side of the lake, the other zones are considered as near shore zones.
The zones on the lake system are distinctly different with respect to several features such as the number of tributary, inflows, siltation, pollution, settlement influences, fishery activity, productivity and many others. In terms of level of income, health and nutritional status, the people in southeastern part are generally better than the other zones.
Generally, the eastern zones which are the southeastern and northeastern zones have wide near shores since these portions of the lake are swallowing up due to high siltation. Fishery activities in this side of the lake are more extensive than in the western side. A significant number of fish cages and fish corrals are concentrated in the southeastern zones where the fish sanctuary is also located.
The water supply of Buhi watershed drains into the lake through several creeks and rivers. Sta Cruz and Iraya rivers are the major inflows. Lake Buhi water level is regulated by a hydraulic control structure (HCS) at the head of Tabao river which is the only water outlet in the lake. Water outflow is toward the south-western side of the lake where the Tabao river and HCS are located.
The impounded lake water is released to the Tabao river channel and passes through the National Power Corporation (NPC) hydroelectric turbine, towards the irrigation canal networks. Hence, lake water outflows are used to provide additional irrigation water supply for about 12,000 hectares of rice lands in the RINCONADA area, at the same time generate electricity for the NPC.
There are also designated lanes for navigational purposes. Most of these have a width of 30 meters and if combine together, they would occupy a significant portion of the lake’s surface area. In addition there are also small fishing boats and ferry boats or passenger’s boats operating in the lake. The number of designated lanes on the eastern side of the lake is much greater than on the western side which is already have an access road.
Stresses and Disturbances
There was also number of commercial growers of swine along the lake’s shoreline that drained their waste into the lake. Households along lakesides were also reported to be draining their septic and other domestic wastes in the lake.
According to the 3rd International Conference on Agricultural Education and Environment, very few of the farmers around the lake had ever practiced soil and water conservation measures. Their most common practice was the use of soil barriers, bench terracing and mulching. Reforestation, riprapping and planting of vetiver as hedgerows were also revealed during FGDs to be done in some uplands barangays of Buhi.
Thus, the perceive effect of non-adoption of soil and water conservation practices include increase in water hyacinth proliferation and decay, decrease in the fish biodiversity and disappearance of sinarapan, algal bloom and lake degradation and chemical pollution, erosion, shallowing of lake, siltation and sedimentation and flooding.
The physical-chemical properties of the water and sediments were above the standards for class C lake indicating that the lake is now in the stage of eutrophication. Eutrophication is an increase in chemical nitrogen or phosphorus compounds in an ecosystem, often resulting in excessive plant growth and decay, in turn leading to lack of oxygen and severe reduction in water quality, fish, and other animal populations.
Based on the lakes system hierarchy (see figure 1), the soil on the northwestern sides are highly erodable and the adjoining water to be more prone of siltation. However, this is not the case, instead, siltation is severe in the eastern part of the lake and can be attributed to the greater number of creeks and rivers, and therefore this site is shallower.
The agricultural pollution like fertilizers and pesticides is coming from the eastern side also of the lake. The eastern side has a higher amount of agricultural activities, the incidence of inundation of the lands are the prime determinants of agricultural chemical pollution inflow into the lake.
Domestic sewage pollution originates from the southern urbanized portion of the lake. The degree of the domestic pollution can be attributed with the absence of good sewage system in the urbanized zone. The poor discipline of the community especially on the waste management, lack of concern for their environment, and the rapid increase of population leads the way for the sewage pollution in the lake.
The use of illegal compounds such as ‘thiodan’ and ‘tuble’ in catching wild fish is another factor affecting the lake system. Thiodan fishing practice is more prevalent in the north western side and at the mouth of Iraya and Cayohosan .
Water hyacinth proliferation and decay is a potential threat to the lake. Proliferation is generally denser in the southwestern side and in the shoreline areas. Since these plants are of a floating type, they move to and from various parts of the lake. The general pattern of water hyacinth inflow can be influenced by wind direction.
According to the National Statistics Office in 2010, the population from the 10 lakeside barangays of Lake Buhi is around 23, 954 and according to the Municipal Fisheries Profile of the Municipality of Buhi the number of fishcage operators and marginal fisherman is 1,034. The number of fish cages in the lake is 16, 562 units, the number of fish corrals (baklad) is 59 units, the fish traps (tabon) is 13 units, the total area designated for fish sanctuary is 86 hectares and the allotted space for aquaculture is 180 hectares.
At present, the lake’s fish cage culture system utilizes about 70-90% of its total 1, 707 hectare surface area. Unregulated aquaculture activities such as illegal construction of fish cages, overstocking of fish and overfeeding produce high amounts of aquaculture wastes that have probably caused massive fish kill.
Majority of the fish cage operators were operating on small scale. Key informants also revealed that local fisherman are acting as dummies of their bigtime operators who are not even residents of Buhi. In addition, in compliance with Municipal Ordinance No. 004 series of 1989, a license fee to operate of only P50.00 is required annually and an annual water rental fee of 20 centavos per m2 of fish cages must be paid to operate a business.
‘Kanuba’ is the local term used by the local fisherman for fish kills; sulfur is the main element in the Kanuba Phenomenon. This phenomenon generally occurs during the months of May to October, when there are weather disturbances and a constant wind pattern. Besides, it is also known to occur prevalently in the south-western side of the lake, which is in general direction of lake water flows. Kanuba begins from the north-eastern side of the lake where there is a sulfur water inflow coming from a sulfur spring at the upland area of Iraya.
Since sulfur is heavier than water, it will precipitate and sinks at the bottom. It is distributed boom water current and mixed with organic matter in the reduced zone of the lake. When a weather disturbance such as southwest monsoon came, there is a tendency for the water to circulate. Consequently, water circulation will bring up the sediments that contain sulfur and other organic matter.
These usually occur when there is a high nutrient content of lake water during an algal bloom. The combination of algal bloom and the upward movement of the lake sediments as well as humus produce toxic substances such as hydrogen sulfide (H2S). These cause the death of the fishes in the area.
Based on BFAR’s Fish Health Section monitoring that instigated in 1998, there are 192 cases of fish kill almost half are being attributed to aquaculture. Five of these fish kill incidents was caused of overstocking of tilapia in fish cages and estimated to cost P33 Million.
On September 2, 2007 a fish kill that resulted from sulfur dioxide from the nearby volcanoes due to the rain southwest monsoon nearly threatened the livelihood of the local fisherman.
In the last quarter of 2011, massive fish kill events occurred and devastated the fish production of the municipality. Leading the preliminary investigation was the Institute for Environmental Conservation and Research (INECAR) of the Ateneo de Naga University, the result showed that the possible cause is that fish cages that covers almost 80% of the lake together with the excess feeds, oxygen depletion and he hydraulic control among others.
Seven months after the initial investigation, the INECAR conducted the first field sampling for the water quality monitoring. It has been found out that:
- Lake is turbid as shown by the low transparency
- The lake has zero salinity which is normal for freshwater ecosystems
- The pH level range from the 14 stations is desirable range for fish production
- All of the sampling stations for phytoplankton are in Toxic Alert Level II
The physical – chemical parameters of the lake, except for turbidity, had reached the normal range. This may be attributed to the natural ability of the lake to recuperate especially that the fish stocks in cages has already been dead, harvested or not renewed, causing for decreased amount of fish feeds being deposited in the water, hence low pollutant input in the lake.
Nevertheless, the turbidity of the lake implies that there are lot of suspended solid particles in the Lake, either silt, soil from erosion, particulate matter, unconsumed fish feeds, and some plankton. According to US-EPA, higher concentrations of suspended solids can serve as a carrier of toxins, which readily cling to suspended particles.
The last report of massive fish kills occurred last August 20-21 this year, Ranilo Leal of BFAR Bicol, said P3 Million worth of tilapia died because of poor oxygen supply and environmental degradation after the number of fish cages operators ballooned.
Inland fish culture had also grown up around the lake. Fish cages operators were overstocking their fish cages requiring the use of more commercial feeds. In one cropping season, with the present inventory of fish cages numbering around 15, 597 cages and a stocking density of around 2,500 tilapia fingerlings per cage of 100m2, around 2,837.5 tons of feeds were used per production cycle. This became a quick source of high nutrient loading in the lake.
Lakelets Sanctuary for Sinarapan
Sinarapan, the smallest fish in the world can only be found in the Lake Buhi, Lake Bato and the Bicol River, where they can be found down to a depth of 12 meters (39ft). This species can reach a length of 2.5 centimeters (0.98 in). Males were usually smaller than females. They are also transparent, except for the black eyes. Nowadays, sinarapan is listed in the International Union for Conservation of Nature (IUCN) red list of threatened species.
According to Victor Soliman and M.F. Hassan A. Sergio’s Managing 'Sinarapan' Mistichthys luzonensis Smith in Lake Buhi, Camarines Sur: Insights from Its Biology and Population Dynamics, “the fish was amazingly abundant in both lakes, Lake Buhi and Bato in the 1930's to the 1960's but almost disappeared in 1979 to the present”.
The catching of sinarapan' in Lake Buhi is prohibited by virtue of Fishery Administrative Order No. 127, Series 1980. The issuance of this order was intended to save the species from neartotal loss. However, two major aspects were lacking for the order to effectively achieve its main objective. First the timing of the order should have been made 2-3 years earlier when catches were not seriously dwindling. Second, the order should have included aspects to rationally manage and conserve the species through ecological enhancement activities.
To complement efforts in protecting the endangered species, the Buhi municipal council passed Resolution No. 80-022, Series 1981 declaring Lakes Katugday and Manapao as 'sinarapan' sanctuaries. Buhi Municipal Ordinance No. 3, Series 1981 which banned the fishing of the small goby in the lakelets was passed shortly thereafter.
The laws enacted for the minute goby delve on the regulatory aspect of resource protection. While this aspect in the three laws is urgent then to prevent an impending stock collapse, adequate provisions should be made for managing the resource to maintain and enhance the integrity and biodiversity of its ecosystem. Such schemes include habitat enhancement, repopulation strategies, community networking and education/information projects. Specifically, the proposals of BUTC to Buhi Municipal Council for the management of Lake Manapao sanctuary are as follows:
- All forms of aquaculture in the Lake Manapao have to be banned
- Introduction of any fish is prohibited
- Watershed enhancement activities should be conducted
- Regulation of non-fishery uses of the lakelet
- Regulation of selective fishing in the lakelet
- Regular maintenance of vegetation
- Prohibition of human settlements in the lake periphery
- Employment of a regular sanctuary manager
- Fund allocation for sanctuary management
- Regulation of 'sinarapan' collection for educational purpose
- Creation of a sanctuary management body
In Lake Buhi, a 15 hectare sanctuary for 'sinarapan' was declared by the municipal government. The sanctuary was established off the barrios San Buena and Sta. Cruz to provide breeding and refuge area for the threatened goby.
Successful management of 'sinarapan' in Lake Buhi will need inputs from both biology and the social dimension of resource management. Effective management of 'sinarapan' in Manapao partly spells success for 'sinarapan' management in Lake Buhi.
The Buhi Municipal Council in collaboration with Bicol University Tabaco Campus BUTC gathered through the barangay council, the residing residents near the lakelet for a forum on the dire need to maintain Manapao and preserve 'sinarapan'.
Coupled with continuing education and information dissemination to the community, these activities will strengthen and widen the network of protection for the sanctuary. Positive results may not be immediately apparent but it is through this process that a clearer perspective of the problem involving socio-economics of the people and the need for conservation for future benefits can be attained.
Lake’s Only Hope
Each fish cages is given an average of 10x10x5 meters and ideally the lake’s carrying capacity is only 10% of its area. “By law, if you’re going to employ capacity management with the lake, or any body of water which is enclosed, it should be 10% lang ang gagamitin” says Ms. Nonie P. Enolva, Chief, Monitoring and Evaluation Section of BFAR Region 5.
Mayor Rey Lacoste signed Executive Order No. 04 prohibiting the installation of new, replacement and additional fish nets including the establishments of fish pens, fish traps, fish orals and tabon; restocking of fingerlings and providing penalty in violation thereof last March 22, 2011
Last July 1, 2011 the Save Lake Buhi Now! Task Force, composed of representatives from LGUs , BFAR, Maritime Police, Philippine Coast Guard divers, Philippine National Police, Philippine Navy, National Commission on Indigenous People, Rotary Club, Tanggol kalikasan, Ateneo de Naga University, National Power Corporation, Fisheries and Aquatic Resource Management Council, and he Philippine Information Agency dismantled some 265 fish cages units.
BFAR has installed 80ps of bouys (16inh diameter) to identify fish cages belt, navigational lanes, buffer zones, and fish sanctuary and waiting for the approval of the Local Government of Buhi to fully implement the 10% usage of lake.
The local government of Buhi and its people used their creativity and develop a booming industry that will utilize the stalks of water hyacinth for processing into new alternative livelihood for the community. The water lilies around the lake are processed into useful products and beautiful artwork such as table runners, placemats, canister bags, slippers and wall décor with the help of Buhi Ecumenical Development Association Incorporated (BEDAI).
The usual members of the BEDAI are women, who are the wives of farmers engaged in the development project of the Department of Agriculture (DA), and to maximize their time, the members sought the help of the Department of Trade and Industry (DTI) and Non-Government Organization (NGO) to start water lily-based-small-to medium-enterprise. The products are available and displayed at the Bicolandia Regional Technology Commercialization Center located at the DA-RFU 5 Compound in San, Agustin Pili, Camarines Sur.
Though these projects may help a lot, Mr. Umbao says the last option he sees to save the lake is to implements the 10% usage of the lake and dismantles the fish cages that do not enter for the allotted space for aquaculture and to decongest the fish cages.
But there was a difficulty in dismantling the fish cages “nahihirapan kame sapagkat kahit sa Local Government Unit (LGU), so yung mga employee ng munisipyo may mga fish cages din pala. So yung mga katulong ko mag dismantle, pag nadaanan yung ano (probably the fish cages owned by a high official in the LGU) di pinapa-sweldo” But Mr. Umbao urge that the lifelong solution to the lakes condition today is to open again the dam to go back its natural cycle.