http://hdl.handle.net/10862/6088 2026-04-06T09:49:34Z 2026-04-06T09:49:34Z Primavera, Jurgenne http://hdl.handle.net/10862/2213 2022-01-24T00:55:55Z 2013-01-01T00:00:00Z

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.

2013-01-01T00:00:00Z Grutas, Marjurie B. Noblefranca, Lydia P. http://hdl.handle.net/10862/5871 2020-06-18T03:52:23Z 2013-01-01T00:00:00Z

Save Lake Buhi now Grutas, Marjurie B.; Noblefranca, Lydia P. Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C. Lake Buhi (Fig. 1) is found in Buhi, Camarines Sur. It is situated at the north-eastern part of Iriga City. The lake has an area of 18 km2 and has an average depth of 8 m. The lake lies in the valley formed by two ancient volcanoes, Mt. Asog and Mt. Malinao. It was formed in 1641 when an earthquake caused a side of Mt. Asog to collapse. The resulting landslide created a natural dam that blocked the flow of nearby streams. Another theory suggests that it was formed by the eruption of Mt. Asog, which is now dormant. The lake is the home of the world s smallest fish, sinarapan (Mistichthys luzonensis). Aside from sinarapan, it also home for other native freshwater fishes such as 'irin-irin' (Redigobius dispar), 'dalag' (Channa striata), 'puyo' (Anabas studines), 'kotnag' (Hemiramphus sp.), 'burirawan' (Strophidon sathete), and native catfish (Clarias sp.). Today, the lake is one of the major aquaculture areas in the Bicol Region where commercial production of Nile tilapia (Oreochromis niloticus) and Mozambique tilapia (Oreochromis mossambicus) is done. The lake supplies the fish demand in the province. But the cyclical occurrence of fish kills threaten the aquaculture industry in the lake. On October 31, 2010, a massive fish kill was again experienced that resulted to almost 75% loss of the lake s fish stocks. The incident calls for inter-agency planning and consultations to address the cause of fish kill and save Lake Buhi from further deterioration. One of the major solutions that arised was the implementation of the ten percent area utilization for aquaculture activity as prescribed in R.A 8550, also known as the Philippine Fisheries Code of 1998. Thus, on March 24, 2011, navigational lanes, buffer zones, fish sanctuaries and reserves, and fishcage belts in Buhi Lake were delineatedupon the request of Mayor Rey P. Lacoste of Buhi.

2013-01-01T00:00:00Z Mutia, Ma. Theresa M. Muyot, Myla C. Torres Jr., Francisco B. Faminialagao, Charice M. http://hdl.handle.net/10862/5846 2020-06-17T06:06:08Z 2013-01-01T00:00:00Z

Seasonality, abundance and biology of tawilis (Sardinella tawilis) in Taal Lake, Batangas Mutia, Ma. Theresa M.; Muyot, Myla C.; Torres Jr., Francisco B.; Faminialagao, Charice M. Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C. A landed fish catch survey was conducted in ten landing centers around Taal Lake from June 2008 to May 2009. Fish catch and unit effort were recorded at 2 days interval for 10 days a month in the established sampling stations. Inventory of fisherfolk, boats, and gear was also conducted. A total of 300 'tawilis' samples per month were measured and dissected to determine the biological and population parameters. Results showed that there were 2,488 fisherfolk, 2,250 fishing boats, and 15,947 units of fishing gear recorded in Taal Lake. Tawilis production in the lake has declined. In 2009, tawilis production was 132 mt, a reduction of 82 % from the average production from 1996 to 2000. However, tawilis remained to be the most dominant fish in the open waters with about 36% of the total fish catch. The major gear used to catch tawilis were gill net and beach seine with catch per unit effort (CPUE) of 6 kg/day and 35 kg/day, respectively. There were 4,646 fish samples analyzed with an average fork length of 9.8 cm, average total length of 11.1 cm and an average weight of 13.2 g. The sex ratio obtained was 1 male to 0.85 female. Spawning of tawilis is all year round with highest gravid samples from March to May and November to December. Tawilis with an average fork length (FL) of 9.9 cm and weighs about 13.9 g has an estimated 4,848 eggs. The analysis of length frequency data has an estimated L8 of 16.8; K value of 0.59; total mortality (Z), 3.46; fishing mortality (F), 1.93; natural mortality (M), 1.54; and exploitation rate (E), 0.56. The fishing mortality was higher than the natural mortality and the exploitation rate exceeded the optimum 0.3-0.5 which implies that there is overfishing of tawilis in the lake.

2013-01-01T00:00:00Z Palma, Adelaida L. http://hdl.handle.net/10862/5844 2022-04-22T03:21:06Z 2013-01-01T00:00:00Z

Water quality trends of the Rinconada lake system and the implications in lake management Palma, Adelaida L. Aralar, Maria Lourdes C.; Borja, Adelina S.; Palma, Adelaida L.; Mendoza, Marlynn M.; Ocampo, Pablo C.; Manalili, Eduardo V.; Darvin, Loureeda C. Monitoring of important water quality parameters were conducted in the Rinconada Lake System in Camarines Sur composed of Lake Bato (3,800 ha), Lake Buhi (1,800 ha), and Lake Baao-Bula (400 ha). Monthly samplings were conducted in 14 stations in Lakes Bato and Buhi and in ten stations in Lake Baao-Bula. For Lake Bato, dissolved oxygen at the surface is within the optimum range of 6.3 mg/L-10.47 mg/L for the wet seasons and 5.7 mg/L - 9 mg/L for the dry seasons but drops drastically at the bottom during the dry season. Critically low mean average of 0.71 mg/L prevailed in the diurnal oxygen trend. High levels of ammonia were recorded in particularly in Station 1 (0.81 mg/l), Station 2 (0.8125 mg/l), and Station 10 (0.8825 mg/l). The mean values of the water quality parameters of Lake Buhi from the surface to a depth of 4 m are within the optimum level. However, critically low dissolved oxygen and high levels of ammonia were recorded at the bottom, indicating the build up of anoxic layer. The Lake is stratified in most months of the year with a gradient difference of 1.74°C during the wet season and 2.15°C in the dry season. Dissolved oxygen, temperature and pH of Lake Baao-Bula is generally within the optimum levels with slight fluctuation in alkalinity. Nitrite (0.7 mg/l) and ammonia (1.5 mg/l) were critically high during the wet season. Results of the water quality monitoring provided management recommendations in establishing aquaculture zones, redesigning of cages and the use of the lakes for aquaculture and fisheries.

2013-01-01T00:00:00Z