LLDA vows to address knife fish problem in lake

MANILA, Philippines - Laguna Lake Development Authority (LLDA) general manager Nereus Acosta yesterday assured the public, especially fisherfolk around the Laguna de Bay, that the agency is doing all it can to address the proliferation of knife fish in the lake.

Recent field surveys showed the considerable presence of knife fish in Calamba City and in the lakeside towns of Los Baños, Bay, Victoria, Pila and Pangil, all in Laguna, and Binangonan and Pililla in Rizal.

In the Sta. Cruz River, a fisherman was able to catch a knife fish, indicating that the fish can swim upstream.

Most knife fish species come from Southeast Asia, specifically in Thailand, Borneo, Malaysia, India, and Sumatra. The knife fish in Laguna Lake are suspected to be the Chitala ornata species.

The knife fish are believed to have found their way into Laguna de Bay in two ways – escaping from ornamental fish farms or aquariums, or deliberately released by hobbyists who wanted to get rid of them.

The knife fish have a distinct silvery gray color, a long knife-like body with an anal fin that looks like a “knife.” A mature knife fish normally have numerous black spots with white rings, two nasal tentacles above their large toothed mouth, and flag-like dorsal fin.

The knife fish look similar to “arowana,” making them a popular ornamental fish.

With such features, the LLDA said the knife fish are not a “monster,” as depicted in recent reports. Though compared to the “janitor fish,” the knife fish have more commercial value than the former and are actually edible.

The knife fish, the LLDA said, can be braised or broiled and can be sautéed in curry or soy sauce. In Thailand, a popular recipe is steamed knife fish with curry, and in Laos, a popular paste is made from finely chopped knife fish.

Juanito Samson, a fishery officer at the Bureau of Fisheries and Aquatic Resources, said the knife fish can be processed and turned into “fishball,” a popular street food, which can be exported to other countries.

As with the janitor fish, the knife fish are now being considered as component for liquid fertilizer for soil applications. In general, fish emulsion is a natural, liquid fertilizer made from ground, dried fish.

Experts are also looking into the potential of knife fish oil as an alternative bio-fuel.

Acosta said he is calling for the cooperation of fishermen and fish pen caretakers in Laguna Lake so that the knife fish can be utilized for their economic uses.

In the succeeding weeks, he said the LLDA would explore the economic potentials of the knife fish, addressing not only their proliferation in the lake but also providing jobs for the people around Laguna de Bay.

Acosta said the LLDA is also reaching out to ornamental fish farm owners and hobbyists to put safeguards in place to prevent aquarium fish species from escaping into the lake.