By Jonathan L. Mayuga
The government will attempt to end the infestation of the pesky knife fish in Laguna de Bay by electrocuting its eggs to control its population, an official of the Laguna Lake Development Authority (LLDA) said.
Reena Buena, officer in charge of the agency’s Community Development Division, said an electrocution gadget developed for the purpose has been approved for experimental use in fish pens by the LLDA and the Bureau of Fisheries and Aquatic Resources (BFAR).
Buena said fish pen operators, who are mostly engaged in milkfish or bangus farming, will be consulted regarding the plan.
“The BFAR has allowed the use of the gadget for fish pens. This year we are going to introduce it to fish pen operators to help control its population,” Buena said.
Only BFAR-trained fish pen operators or their representatives will be allowed to electrocute knife fish eggs. Electrocution as a method of catching fish is not allowed under the law, but the government allowed fish pen operators to use it to contain the pesky fish.
Knife fish infestation in Laguna de Bay continues to threaten the lake’s biodiversity. It has been harming the livelihood of small fishermen and fish pen operators since 2012.
In 2014 the BFAR reported that its population significantly went down, based on fish-catch observation among fishermen. The volume of knife fish in the catch composition, according to the BFAR, declined to 15 percent in 2014, from 40 percent in 2012.
Last year, however, it went up to 22 percent, indicating that knife fish in Laguna de Bay is again increasing.
“Small fishermen are affected because, instead of catching native fish, they catch knife fish. There should no be let up in our operation to end the infestation of knife fish to safeguard the livelihood of fishermen,” Buena said.
The LLDA said the knife fish infestation affects Calamba City, Los Baños, Bay, Victoria, Pila and Pangil, in Laguna; and the towns of Binangonan and Pililla; in Rizal.
Among the programs initiated by the Interagency Task Force on the Proliferation of Knife Fish include the buyback scheme wherein knife fish caught by fishermen are bought at P20 per kilogram.
The Department of Social Welfare and Development, LLDA and the BFAR—which are all members of the task force—allocated funds for cash-for-work programs wherein people in the communities surrounding the lake are tapped to catch it or collect its eggs.
These initiatives, however, failed to prevent the proliferation of the knife fish.
Buena said some of the knife fish bought by the task force from fishermen as part of the buyback scheme were processed, but most were just buried.
A recent study about the knife fish infestation conducted by the BFAR and the Department of Science and Technology revealed that a kilo of knife fish can consume 7 kg of native fish.
Fishermen observed that local fish such as ayungin and biya in Laguna de Bay are becoming scarce. They expressed fear that local fish species will soon become extinct because of the knife fish infestation.
Although it is safe to eat and is priced at only P20 per kg, consumers still prefer to buy other popular native fish species which could cost as much as P120 per kg.
Even processed knife fish meat, done through research and development, for value-adding purposes, failed to convince consumers to buy the fish or its products.
An invasive alien species, the knife fish’s appearance is distinct. Its color is silvery gray and it has a long knife-like body with an anal fin. Unlike the janitor fish, the knife fish is not a “monster” fish. In fact, it has aesthetic similarity with the popular aquarium fish, arowana.
The knife fish infestation in Laguna de Bay was first reported by fishermen in 2012.
The BFAR believes that the knife fish may have been accidentally released into the river tributaries by hobbyists and it eventually found its way into the Laguna de Bay.