Marikina River - Ecology

Ecology

Marikina River is on the verge of an ecological imbalance as a strange species of fish has dominated its ecosystem. Since the late 1990s, the Marikina River has been infestated by janitor fish. Before, the river was thriving with local species like tilapia, martiniko, ayungin and biya.

The growing fish population has prompted the city government to launch a new program to control their number. The city issued Ordinance 004, series of 2007, launching Janitor Fish Eradication Drive in the City of Marikina, granting cash incentives to participants, appropriating annually fifty thousand Pesos (P50,000.00) for the purpose

A scientific study of the species found in five locations in the Laguna de Bay tributary system, including the Marikina River, revealed that the specimen of janitor fish previously reported as Hypostomus plecostomus actually belong to the genus Pterygoplichthys, family Loricariidae. The collected specimens for this study consisted of two species; Pterygoplichthys disjunctivus and Pterygoplichthys pardalis. Both species were collected from the Marikina River. Only the species disjunctivus was collected from Pasig River.