Invasion biology f suckermouth armored catfishes (Pisces: Pterygoplichthys

Suckermouth armoured catfishes (SACs) known locally as janitor fish have been introduced into Philippine waters. SACs have been thriving in areas in the Laguna de Bay basin and are considered invasive by way of anecdotal accounts that the fish is causing negative effects to humans and the environment. This study intends to shed light in the biology of this invasion so appropriate plans to mitigate negative effects may be put in place. The results of the study reveal the following: 1) there are two species of SACs in the Laguna de Bay area namely, Pterygoplichthys pardalis and Pterygoplichthys disjunctivus 2) there is a thriving SAC population that has equal sex ratio between males and females, females that mature at short lengths, females with high fecundity, and a 10- month breeding season 3) SACs are interacting with native species by being an opportunistic detritivore, salinity tolerant, low oxygen tolerant, and protected by armor 4) SACs are not a likely cause of biodiversity loss and 5) SACs are not a likely cause of habitat destruction and alteration. With the cost of managing invasive species, the Philippines should prepare a plan for this invasive species that takes into account the status of existing economic and social capacities and the status of environment of the invaded areas