Details of this species in Philippines Status: Alien
Invasiveness: Invasive
Occurrence: Established
Source: Chavez et al, 2006; Hubilla et al, 2007; Joshi, undated Arrival Date:
Introduction: Unknown Species Notes for this Location:
Pterygoplichthys disjunctivus and P. pardalis were collected from several sites, in Laguna de Bay, Philippines. They were collected from medium-velocity rivers no more than two meters deep near the riverbanks at sites including Marikina River in Marikina and Pasig Cities; Pasig River in the City of Manila; Catmon Creek in Bay, Laguna; Banilad Creek in Siniloan, Laguna; and Laguna de Bay in San Pedro, Laguna. Most of the drainages where specimens were collected have a muddy and murky bottom. Water quality in these areas can be characterized generally as polluted because these drainages receive waste materials and even sewage from households and industries. Both are believed to have been imported to the Philippines as aquarium fish. A wider distribution of Pterygoplichthys species outside of the Laguna de Bay basin is suspected due to its popularity and the extent and briskness of the aquarium fish trade in the Philippines. Fish are believed to have accidently escaped from breeding ponds along the lake when typhoon Rosing hit the country in 1995 (Hubilla et al., 2007). There have been reports of "janitor fish” sightings in streams and rivers in Zamboanga City and Aparri Cagayan (Chavez et al, 2006). P. disjunctivus has invaded the Agusan Marsh as well and may be found in the lakes rivers and creeks of the municipalities of Talacogon, La Paz, Loreto, Bunawan, Rosario, San Francisco, Veruela, and Sta. Josefa (Hubilla et al, 2007). P. pardalis has also become invasive in the Marikina River (Metro Manila), Lake Paitan in Cuyapo, and Nueva Ecija (Joshi, undated). Management Notes for this Location:
Researchers have recommended a number of management schemes for controlling Pterygoplichthys spp. in the Agusan Marsh including conducting a long term assessment to monitor populations, purchasing sailfin catfish from fisherman for companies that can use them as raw material and strengthening the enforcement of wildlife and environmental laws (Hubilla et al., 2007).
Recently a bounty system for the eradicated of the “janitor fish” has been launched by the City Government of Marikina. The live fish is brought at the price of P5 per kilogram and then destroyed. A World Bank-funded project for the conversion of the species into fishmeal is being implemented by the Laguna Lake Development Authority in cooperation with a farmer’s cooperative in Laguna (Joshi, 2006).
Experiments are also underway to use Janitor Fish for the Fish Amino Acid (FAA) concoction for Natural Farming Technology System (NFTS). Janitor fish is combined with molasses and fermented to produce the concoction to use on corn farms as fertiliser. (Agusan Marsh FOCAS, 2008).
Other uses of janitor fish have also been proposed, including using the oil of the fish to make biofuel and soaps (Sarmiento, 2006). Impacts:
Human nuisance: Pterygoplichthys disjunctivus and P. pardalis have been reported interfering with fishing activites by displacing more desirable fish and destroying cages and nets (Chavev et al, 2006).
Reduction in native biodiversity: Pterygoplichthys disjunctivus and P. pardalis are reportedly causing a decline in native fish in Laguna de Bay, Philippines (Chavez et al, 2006). Last Modified: 10/06/2010 1:55:22 p.m.
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