An environmental assessment of the aquaculture potential of Lake Gawaan, Lake Lenneng and Lake Banao/Danum at the Mt. Province.
MetadataShow full item record
This study reviews the existing conditions of the three Mt. Province lakes: Lake Gawaan, Lake Lenneng and Lake Banao/Danum. Three mechanisms were employed. First is the overview of the resource capabilities. This includes the geographical, physical and biological characteristics, as well as the identification of nearby communities and the possible market distribution channels. The physical characteristics are the watershed type, color of water, kind of shoreline, source of water, water fluctuation levels and transparency/turbidity. Biological and chemical characteristics comprise the primary productivity, dissolved oxygen, nitrate, pH, ammonia, and stock availability (catch composition, gear type, seasonal distribution and production rate). The second mechanism is the understanding of the limitations of the area and development prospects which could cater to the needs of the growing population. This tackles suitable aquaculture practices that may be adopted at the areas concerned in order to increase fish production at the Mt. Province. The last mechanism is to determine if the combined efforts of the non-government organizations, government agencies and other concerned groups could be improved to prevent a piece-rate resource development program. Results showed that favorable conditions for fish culture are present in the three lakes. Culture of fish in net cages and pens appears suitable for the lakes.
Dang-awan, R.G., Estima, M., Gayagay, P., Pagtan, A. and Ramos, M.A.A. (2001). An environmental assessment of the aquaculture potential of Lake Gawaan, Lake Lenneng and Lake Banao/Danum at the Mt. Province (Abstract only). In CB Santiago, ML Cuvin-Aralar and ZU Basiao (Eds). Conservation and Ecological Management of Philippine Lakes in Relation to Fisheries and Aquaculture (p. 152). Southeast Asian Fisheries Development Center, Aquaculture Department, Iloilo, Philippines; Philippine Council for Aquatic and Marine Research and Development, Los Baños, Laguna, Philippines; and Bureau of Fisheries and Aquatic Resources, Quezon City, Philippines.
PublisherSEAFDEC Aquaculture Department; Philippine Council for Aquatic and Marine Research and Development; Bureau of Fisheries and Aquatic Resources
Showing items related by title, author, creator and subject.
Assessment of local government's implementation of open access policy in Taal Lake, Philippines: Effects on lake conservation and management. MT Mercene-Mutia - 2001 - SEAFDEC Aquaculture Department; Philippine Council for Aquatic and Marine Research and Development; Bureau of Fisheries and Aquatic ResourcesThe effects of local government's implementation of the current national policy on open access in municipal fisheries are assessed in terms of their impact on the fishery resources of Taal Lake. Local officials and fisherfolk were interviewed and their responses were analyzed for trends in perceptions on how local open access policies affect fishing practices and productivity in the lake. A policy matrix containing certain areas of concern of local governments related to sound decisionmaking on lake fishery was designed. The study shows that local government implementation of open access policy in Taal Lake tends to have negative effects on the lake's fisheries. Open access allows for the unregulated entry of fishing practices like fish cage culture which tend to increase the pollution load in the lake. Pollution due to fish farming in cages seems to even exceed loads from domestic wastes and agricultural runoff. While fish cages flourished in the lake, the income of small fisher folk has declined because of dwindling catch from capture fisheries. It is recommended that national government agencies (e.g., Department of Agriculture, Bureau of Fisheries and Aquatic Resources, Department of Environment and Natural Resources) should forge an agreement with local government units for a continuing assessment of the fishery resources in Taal. This needs to be coupled with technical assistance to undertake sustained efforts to improve the conservation, productivity and management of the lake's aquatic resources. There is also a need to increase the budgetary allocations for new research and extension activities to address problems and issues of the fishery sector in the lake and for upgrading the capability of local and sectoral policy and decision makers on the lake's fisheries.
Induced ovarian maturation and rematuration by eyestalk ablation of Penaeus monodon collected from Indian ocean (Phuket province) and Songkhla lake. N Ruangpanit, S Maneewongsa, T Tattanon & P Kraisingdeja - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development CenterBecause of the difficulty involved in maintaining a supply of sexually mature female shrimp for larval production in hatcheries, experiments on induced ovarian maturation in tiger shrimp, Penaeus monodon by eyestalk ablation were carried out from March to August, 1983. These shrimps were collected from two areas of Thailand: Phuket on the Indian Ocean and Songkhla Lake with entry to the Gulf of Thailand. Every female had one eyestalk pinched before being stocked together with males in various female-male ratios in 50-ton cement tanks with continuous water flow. The shrimp were fed 10% of their body weight daily with a diet of 90% green mussel (Mytilus edulis) and 10% cow liver. Results show that of those female shrimps collected in the Phuket area which is a natural spawning ground, 51% became gravid.However, of those collected in Songkhla Lake which is not a spawning area, only 19.51% became gravid. There was also a large difference in the number of days between eyestalk ablation and first spawning: 4-5 days for the Phuket samples and 20-30 days for those from Songkhla Lake. The survival rate of the larvae until P20 averaged 8.5% (total 732, 259) for the Phuket samples and 4.0% (total 300,000) for the Songkhla Lake samples. Results show mass mortality during the nauplius and mysis stages of shrimp from both locations which may indicate a greater susceptibility to bacterial and fungal infections in larvae produced from artificially matured females. Further studies should be undertaken to determine the proper nutritional diet for maximum production of gravid females, and to discover methods to increase sperm production in males from areas other than natural spawning grounds.
Effects of low nitrogen-phosphorus ratios in the phytoplankton community in Laguna de Bay, a shallow eutrophic lake in the Philippines The effects of low nitrogen-phosphorus ratios on microalgae from a large eutrophic freshwater lake in the Philippines were investigated. Natural microalgal populations from Laguna de Bay, the largest lake in the Philippines, were cultured using three different nitrogen-phosphorus weight ratios (2N:1P; 6N:1P and 12N:1P) at two phosphorus concentrations (0.25 and 0.5 mg l–1) in each case. The growth and genera composition of the cultures under the different treatments were followed for a 12-week period. Community level responses were assessed based on species richness (s), Shannon-Wiener Index (H’), Simpson Index (λ) and Evenness (J’). Among the different microalgal groups, only the chlorophytes showed a significantly higher density in response to the 12N:1P treatment at the higher P concentration, indicating that the nutrient ratio had a significant interaction with the nutrient levels used in the experiments. The genera found in the different treatments were generally similar; however, the degree of dominance of some varied with treatment during the experiment. The succession of dominant genera also differed among the N:P treatments. The diatoms like Fragilaria, Aulacoseira (= Melosira) and Nitzschia dominated the lowest N:P. On the other hand, chlorophytes (Kirchneriella and Scenedesmus) dominated the highest N:P treatment, particularly from the second to the seventh week of the experiments with the diatoms becoming co-dominant only towards the eighth week until the end of the experimental. The 6N:1P treatment showed a mixed dominance between the diatoms and the chlorophyte genera. The various indices of diversity indicate significantly lower diversity only in the 12N:1P at 0.5 mg l–1 P and not in 12N:1P at 0.25 mg l–1 P.