Department of Agriculture
Bureau of Fisheries and Aquatic Resources
Regional Office No. 5
San Agustin, Pili, Camarines Sur
LAKE BUHI NEEDS CAPACITY MANAGEMENT
A call for capacity management for Lake Buhi in Camarines Sur is necessary for its sustainable use. The Bureau of Fisheries and Aquatic Resources (BFAR) in Bicol estimates the fish kill that started on October 29, 2010 costs P10M in revenue and 100MT production losses.
Based on BFAR Fish Health Section monitoring records that commenced in 1998, there are 192 cases of fish kills with almost half of the causes being attributed to aquaculture. (BFAR-PHILMINAQ, 2007)
Five fish kill incidents were observed in 1998 with the most significant being the Lake Buhi case which was caused by overstocking of tilapia in fish cages and estimated to cost P33M. Bad aquaculture practices such as overcapacity, overstocking and overfeeding resulted in the negative impacts in the environment and the stocks itself. Overcapacity refers to the establishment of structures such as cages and pens beyond the carrying capacity of the lake, river or coastal area. Too many pens and cages that obstruct the free flow of water and physical congestion are signs of overcapacity. Overstocking, similar to overcapacity but limited to the confines of a cage, pen or pond unit, means that the number of fish stocked is beyond the recommended number. Overstocking ultimately results to higher demand for feed, higher wastage and increased demand for oxygen and nutrients from the water.
Overfeeding, either too much feeds or use of inefficient feed low-quality binders, is usually done to hasten growth and result in bigger sizes.
Aquaculture produces wastes in the form of particulate (mainly the uneaten food and feces) and soluble substances (excreta) which increase biochemical oxygen demand, nitrates and phosphates in receiving waters. The risk of negative impacts of aquaculture wastes is greatest in enclosed waters like the Lake Buhi where there is a poor rate of water exchange. In these conditions, aquaculture production can lead to a build-up of organic sediments and addition of nutrients to the water column which, in turn, could lead to secondary effects like eutrophication, water hyacinth bloom and very low dissolved oxygen levels. These factors contributed to the recent fish kill incident in Lake Buhi.
Based on the water quality monitoring of Lake Buhi by BFAR-Bicol personnel on November 2 and 4, 2010, the lake’s dissolved oxygen was very low; the ammonia nitrogen level was very high in eleven stations monitored in the lake and high toxic traces of hydrogen sulfide were detected in five stations as compared to the optimum ranges set by the South East Asian Fisheries Development Center (SEAFDEC). This critical water condition of the lake probably led to the massive fish kill in Lake Buhi.
BFAR-Bicol Regional Director Dennis V. del Socorro appeals to the Local Government Unit of Buhi for a lake capacity management. He said that the bureau is very much willing to provide technical assistance on managing inland aquaculture and its impacts following the fisheries laws and regulations. Ideally, lake’s carrying capacity is only 10% of its total area. At present, Lake Buhi’s fish cage culture system utilizes about 70-90% of its total 1,707-hectare surface area. Lake Buhi is in its brink of unsustainable use. Thus, to hash out issues, advocacy on good aquaculture management practices must be undertaken.
Accordingly, Mayor Rey Lacoste cited that fish kill happens annually, the latest being the worst affecting 80% of Lake Buhi’s fish cage operation. LGU-Buhi plans to implement strategic actions to help mitigate fish kill incidents and at the same time support the affected artisanal fisherfolk by way of clean-up activities and intensify alternative livelihood sustainable for the fisherfolk, among others. (nonie_enolva)
For more info, contact:
NONIE P. ENOLVA
Chief, Monitoring and Evaluation Section
CP # 0919-4970286
Telefax: (054) 361-2326