LakeCon2011
http://hdl.handle.net/10862/5840
2nd National Congress on Philippine Lakes2024-03-28T13:12:13ZThe Agusan Marsh and the Agusan River Basin: The need for science-based development and management
http://hdl.handle.net/10862/2213
The Agusan Marsh and the Agusan River Basin: The need for science-based development and management
Primavera, Jurgenne
Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C.
2013-01-01T00:00:00ZEstablishment of fish reserve area in Taal Lake, Philippines
http://hdl.handle.net/10862/5857
Establishment of fish reserve area in Taal Lake, Philippines
Mutia, Ma. Theresa M.; Zafaralla, Macrina T.; Muyot, Myla C.; Molina, Genaro M.; Rayos, Joseph
Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C.
In 2007, The Protected Area Management Board (PAMB) of the Department of Environment and Natural Resources (DENR) approved a Unified Rules and Regulations (URR) for fisheries in the Taal Volcano Protected Landscape (TVPL). One of the provisions in the URR was the establishment of a fish reserve area which was also adopted in the newly approved TVPL Management Plan in 2009. The reserve area was about 1,000 hectares in the southern lakeside of volcano island under the municipalities of Balete, Matas na Kahoy, Sta. Teresita, and Cuenca. The boundaries were established by the Provincial Government of Batangas using a Global Positioning Satellite (GPS) and exact coordinates were identified. This study was conducted to gather baseline information on the biological, physical and chemical characteristics of water and the presence of fish larvae and fish early life in five sampling stations in the reserve area. The study was conducted for 4 months in 2010 (March, May, August, and September). Survey on fish larvae, egg and plankton were conducted using vertical and horizontal plankton towing. Physico-chemical parameters of water such as temperature, water depth, transparency, dissolved oxygen, pH, nitrites, and alkalinity were measured using a thermometer, echo sounder, secchi disk, and Lamotte test kit for freshwater, respectively.
Preliminary results showed that there were fish larvae present in all stations except in Station 3, while all stations have the presence of fish eggs. There were three families of fish larvae identified which include Atherinidae, Blennidae and Syngnathidae. A total of 16 species of phytoplankton and 14 species of zooplankton were identified in all stations. The water depth ranged from 3.2 m. to more than 75 m. Station 1 was the deepest while Station 5 was the shallowest where abundant macrophytes were also observed. Water transparency in all stations ranged from 2.1 to 2.7 m. The temperature ranged from 30.5 to 32°C. Dissolved oxygen ranged from 5 to 7.1 ppm while the pH ranged from 4.0 to 9.0. Nitrites ranged from 0 to 0.1 ppm while alkalinity ranged from 185 to 220 ppm. High temperature and low pH readings were observed in May before PHIVOLCS announced Alert Level 2 in June 2010. Fishing operations of gill net, beach seine, ring net, and spear gun were also observed in the area.
2013-01-01T00:00:00ZTime- and space-related water quality fluctuations and phytoplankton community dynamics in Lake Sampaloc of San Pablo City and Lake Crocodile of Los Baños, Laguna, Philippines
http://hdl.handle.net/10862/5865
Time- and space-related water quality fluctuations and phytoplankton community dynamics in Lake Sampaloc of San Pablo City and Lake Crocodile of Los Baños, Laguna, Philippines
Tamayo-Zafaralla, Macrina; Lambio, Karl Angelo; Gado, Jeric; Pasagui, Troy
Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C.
A study was done from June 2008 to June 2010 to compare the limnological features of two lakes in Laguna Province, namely, Sampaloc, a maar lake of San Pablo City, and Crocodile of Los Baños. Temporal variations were analyzed with emphasis on trophic state parameters monitored at three and two stations, respectively; and with three replicate areas/station. Statistical analysis used was the Kruskall-Wallis ANOVA and Pearson correlation analysis.
Both lakes had significant to very highly significant seasonal differences in terms of water temperature (WT), total hardness (TH), nitrite-N, total inorganic nitrogen (TIN), soluble reactive phosphorus (SRP), total P (TP), and chemical oxygen demand (COD). Wet season (WS) lake warming in Lake Sampaloc possibly resulted from advective and convective heat transfers. In Lake Crocodile, solar heating is suspected because of cooling in January and warming in summer. In the dry season (DS), all ionic N forms and TIN spiked, implying improved N storage while oxidative N conversion improved and accompanied by enhanced algal growth. In Lake Crocodile, the WS saw increasing TH and NO2-N. In both lakes, elevated SRP and TP in DS was possibly caused by increased evaporation rates as P-augmenting human activities continued translating in increased pollution as evidenced by rising COD and Chl a. Chl a correlated with SDT, TA, EC, NO3-N, TIN, SRP and TP. The data is summarized in Table 1.
Chl a ranges and overall means put Lake Sampaloc under eutrophic category, while Lake Crocodile is under mesotrophic to low-eutrophic. Species richness was higher in Lake Sampaloc with a cool month spike, the Cyanophyceae and Chlorophyceae exhibiting balanced representation. The Shanon-Wiener index of diversity, H range was 0.16-1.87. and the top three dominant species were Microcystis, Aulacoseira and Aphanocapsa.
Lake Crocodile was mesotrophic to low-eutrophic with species richness spike in June and February, respectively. There were four to nine species found per station per sampling; the Shannon-Wiener H range is 0.07-0.96; and Microcystis, Coelastrum and Chroococcus disperses as dominants. Figure 1 shows the diversity indices for phytoplankton in the two lakes.
2013-01-01T00:00:00ZA fisheries in crisis: Threatened biodiversity and fish production of Lake Mainit, northeastern Mindanao
http://hdl.handle.net/10862/5867
A fisheries in crisis: Threatened biodiversity and fish production of Lake Mainit, northeastern Mindanao
Biña-de Guzman, Asuncion; Uy, Wilfredo H.; Gorospe, Jessie G.; Openiano, Alita E.
Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C.
Lake Mainit in Northeastern Mindanao is an important shared resource of the Provinces of Agusan del Norte and Surigao del Norte. It is distinguished as the deepest (219.35 m) and the fourth largest (17,060 ha) lake in the Philippines with 28 river tributaries and only one outlet river that flows into Butuan Bay. The most recent assessment in 2007-2008 showed that at least 15 species of aquatic plants, 41 species of fish, five crustaceans, and 10 mollusks occur in Lake Mainit and its outlet Kalinawan River. Lake Mainit has a very diverse fish community classified into three different groups, namely, true freshwater fishes (lake and riverine), amphidromous fishes, and catadromous fishes. This highly productive and diverse wetland ecosystem supports a thriving freshwater fishery and the livelihood of more than 3,000 fishers using a highly diverse fishing gear technology. The municipality of Kitcharao, Agusan del Norte has the largest contribution to fisheries production (Fig. 1).
Environmental and human factors have threatened the biodiversity and productivity of the Lake in recent decades. Certain species of fish are feared to have been extinct; at least 13 of 37 species reported by Pauly et al. (1990) were no longer encountered in the present study. More than 65% of the fish are migratory between the lake and Butuan Bay through the Kalinawan River.
The population of the once abundant giant mottled eel (Anguilla marmorata) has drastically declined, resulting from massive fishing on adult eels during their seasonal spawning along Kalinawan River. The native white goby (Glossogobius giuris), locally known as pijanga, remains the most important fishery resource in Lake Mainit (Fig. 2), but the current fish catch is about 63% of the 1997-98 production as reported by Galicia and Lopez (2000). Many species are caught in progressively smaller sizes, resulting in lower economic value and hence, marginal fisher incomes. Pollution, unsustainable fishing practices, high fishing pressure, and lack of enforcement of fisheries policies have drastically reduced the annual fish catch from 15,108 t in 1980-81 to only about 831.50 t in 2007-08, which is only about 5.5% of the production level 26 years ago.
Lake Mainit experiences the typical syndrome of a threatened fisheries resources: biodiversity loss, high fishing pressure, use of unsustainable fishing gears and methods, declining fish catch and catch-per-unit-effort, decreasing size of fish caught, and marginal or meager fisher incomes barely enough to provide for the basic daily needs like food, health, and children s education. The Lake Mainit Development Alliance (LMDA), an inter-LGU alliance among the eight municipalities around the lake, provides a ray of hope for this threatened resource. A fisheries management program is being integrated into the Lake Mainit Development Agenda to help restore Lake Mainit fisheries resources to sustainable levels.
2013-01-01T00:00:00Z