Researchers warn vs 'alien fish' in Laguna de Bay

Photo of the confirmed Barbonymus schwanefeldii (tinfoil barb) specimen caught in Laguna de Bay in 2024. By Mariko Aboganda via Ateneo de Manila University

MANILA — Biologists from the Ateneo de Manila University on Tuesday confirmed the presence of tinfoil barb or Barbonymus schwanefeldii in Laguna de Bay, which they said "poses a threat to native fish by outcompeting them for food and breeding sites."

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Tinfoil barb, a fast-growing omnivore, is a popular aquarium fish native to Southeast Asia but not the Philippines.

"The tinfoil barb’s spread could worsen the already degraded state of Laguna de Bay, which provides fisheries, water, and flood control for millions," researchers said, noting that Lagune de Bay is Philippines' largest freshwater lake.

The authors warned that establishment of tinfoil barb in local fishing grounds could further stress Laguna de Bay.

"If this spread continues unchecked, it could mirror the ecological disruptions caused by other invasive fish worldwide—such as tilapia or janitor fish—leading to biodiversity loss and irreversible changes to aquatic food webs," it said.

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The ADMU biologists who worked on the study, posted by Philippine Journal of Systematic Biology, are the following:

• Kent Elson Sorgon

• Marjorie Juliana Martinez

• Andrei Justin So

• Mariko Franccesca Aboganda

• Jazreen Nicole Parungo

• Aeris Johanne Poricallan

• Keona Tiffany Prieto

• Mellissa Jewel Magday

• Alexa Charlize Geronimo

• Ma. Vianca Julia Anupol

• Derreck De Leon

The Ateneo researchers said their confirmation "highlights the largely unmonitored trend of invasive freshwater fishes establishing themselves in Philippine inland waters, with potential long-term ecological consequences."

PHOTO: Harvesting in Laguna Lake

"We hope that local authorities can help raise awareness and put in further monitoring efforts, not just for this but for other invasive species as well," said Sorgon, the lead researcher.

Laguna's Office of the Provincial Agriculturist last month conducted a retrieval operation of tinfoil barb and other invasive fish species from the rivers of the municipalities of Pagsanjan and Lumban.

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