Graduate School, University of Santo Tomas, Manila, 1008 Metro Manila, Philippines
Department of Biological Sciences, College of Science, Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, 1008 Metro Manila, Philippines
Corresponding author
asgilles@ust.edu.ph
The number of non-native fish species introduced into the Philippines has steadily increased over the last decades, similar to other Southeast Asian countries. This trend of non-native species introductions is of high concern for the conservation of the native aquatic biota of the country, as invasive fishes are known to be responsible for a wide range of detrimental effects. In this study, the 13 non-native freshwater fish species recently reported for Ramsar-listed Lake Naujan (Province of Oriental Mindoro) were screened for their invasiveness risk under current and predicted climate change scenarios. Of the screened species, 23.1% and 61.5% were ranked as high risk under current and future climate conditions, respectively. The higher-risk species were redbelly tilapia Coptodon zillii, Nile tilapia Oreochromis niloticus, and guppy Poecilia reticulata. These findings indicate a high likelihood that the already threatened aquatic biota of Lake Naujan will be further affected by the presence of the resident non-native fish species in the near future. Recommendations include: (i) implementation of an introduction vector and pathway analysis; (ii) establishment of a comprehensive list or database of potentially invasive or prohibited species; (iii) continuous monitoring and surveillance of fish activities in the lake; and (iv) implementation of a comprehensive, government-led information, education and communication campaign. The outcomes of this study are also meant to serve as a foundation for the development of shared regulations to control the international trade of non-native fish species not only in the Philippines but also among southeast Asian countries.