Invasive fishes or non-native species threatens conservation of freshwater fishes.
Prompted by this concern, the 2nd National Forum on Invasive Fishes tackled awareness, containment, and management strategies for invasive species recently.
Held at Tanay, Rizal, the forum was jointly sponsored by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD) and the Bureau of Fisheries and Aquatic Resources (BFAR).
The forum was held following reports on unwanted species in Laguna de Bay, Taal Lake, and other major water bodies.
Mapaminsalang Dayuhang Isda, Pigilang Makawala Sa Mga Ilog at Lawa, the forum’s theme, served as an urgent call for containment and management strategies of invasive fishes.
Dr. Dalisay Fernandez, Director of the Inland Aquatic Resources Division (IARD) of DOST-PCAARRD stressed the need for a science-based approach to managing invasive fishes—one that is anchored on knowledge of the fish’s biology and ecology.
Citing the broad spectrum of strategies being adopted by the Inter-agency Task Force on the Containment of Knifefish in Laguna de Bay, keynote speaker, Mariel Espiritu, Assistant General Manager of the Laguna Lake Development Authority (LLDA), highlighted the need for concerted action.
According to Academician Rafael Guerrero III and Dr. Ravindra Joshi, 60 freshwater fishes were introduced in the Philippines for aquaculture, recreational fishing, ornamental fish trade, and biological control. While some invasive species have become commercially important, many species have been observed to displace local species, disrupt food chains, degrade water quality due to burrowing activities, and introduce diseases and pathogens.
Guerrero and Joshi called for a comprehensive approach to controlling invasive species through strict enforcement of regulation on live fish imports; vigilant monitoring of fish introduction and spread; community involvement in monitoring and control; and science-based approaches, including knowledge of the fish’s biology and ecology.
Michael Andayog of BFAR discussed the various laws relating to exotic fish introduction and trade, citing specifically the provisions of the Philippine Fisheries Code (RA 8550) and Wildlife Resources Conservation and Protection Act (RA 9147).
Dr. Christine Casal of Fish Base discussed the invasion curve and the impact of the aquarium fish trade as one of the pathways for introduction of invasive species. She emphasized the importance of risk assessment as a cost-effective method to control the entry of invasive species. She also identified several parameters for conducting risk assessment studies.
Researchers from various agencies reported on the status as well as the management strategies for five invasive fishes, namely jaguar gapote, black chin tilapia, Thai catfish, knifefish, and janitor fish.
Ma. Theresa Mutia, Center Chief of the National Fisheries Biological Center–BFAR showed the growing dominance of the jaguar gapote, Parachromis manguensis in Taal Lake and the black chin tilapia, Sarotherodon melanotheron.
The growing dominance of black chin tilapia in Manila Bay, meanwhile, was discussed by Dr. Mudjeekeewis Santos, Scientist from the National Fisheries Research and Development Institute (NFRDI). Both species are known to prey on fish larvae and small fishes.
Government agencies are now taking action to control the damages caused by invasive fishes. Dr. Ravelina Velasco of Central Luzon State University (CLSU) Freshwater Aquaculture Center discussed the impacts of the Thai catfish, Clarias batrachus, on the native catfish, which the university is trying to propagate through a program.
Dr. Adelaida Palma, Center Chief of the National Inland Fisheries Technology Center in Tanay, Rizal, presented the strategies being implemented to contain knifefish, which is now the second largest catch in Laguna de Bay.
As lead agency of the Knifefish Technical Working Group, BFAR is coordinating the implementation of various initiatives against the said invasive species. These include:
- massive retrieval of knifefish through a buy-back scheme;
- cash for work program;
- development of value-added products; establishment of a fish processing plant in Pila, Laguna;
- distribution of fishing gears;
- information, education, and communication (IEC) campaigns;
- establishment of a website about invasive species, and
- development of gadgets to destroy the eggs of knifefish.
These initiatives are complemented by a monitoring program to determine changes in fish populations of knifefish.
Lastly, an LLDA representative presented the results of the utilization of janitor fish as fishmeal, which was a World Bank-funded program.
Parameters on risk assessment of fish introductions were also identified during the forum in consonance with RA10654 which amends the Philippine Fisheries Code. The said law bans the importation, introduction, or breeding of foreign or exotic aquatic species without conducting risk analysis.
The forum was capped by the “Tanay Resolution,” which identified key actions on how to manage the problem of invasive alien species in the Philippines. The resolution highlighted some of the recommendations presented by the plenary speakers.