New records of an Invasive Calanoid Copepod, Arctodiaptomus dorsalis (Marsh, 1907) in freshwater ecosystems in the Bicol Peninsula (Luzon Is., Philippines)

Abstract

Arctodiaptomus dorsalis is a Neotropical freshwater calanoid species that is now widely distributed throughout the Philippines because of its ability to adapt well to eutrophic environments and aquaculture. A previous survey already confirmed the presence of A. dorsalis in three lakes in the Bicol peninsula. The primary goal of this study was to determine the extent of the occurrence of A. dorsalis in Bicol given its ability to displace native calanoid species. Samples were collected from 34 freshwater bodies throughout the Bicol Peninsula spanning the provinces of Camarines Norte, Camarines Sur, Sorsogon and Albay. Our results show that A. dorsalis is now recorded from five freshwater ecosystems in Bicol that are linked either through natural connections, aquaculture, or water system constructions. This includes manmade structures such as Lago del Rey and the Camarines Sur Water Sports Complex, and natural freshwater ecosystems such as Lake Buhi, Lake Danao and the Bicol River. Except for Lake Buhi, the other four sampling sites are new locality records for A. dorsalis. Translocation of fishes and passive dispersal through natural or man-made channels aided the dispersal of A. dorsalis in these areas. Though only 14% of the total sampling sites were positive for A. dorsalis, it occurred in the larger water bodies (natural and manmade lakes and large rivers) in the region including one, Lake Buhi, that previously contained native calanoid species such as Tropodiaptomus vicinus. Our results confirm the absence of Tropodiaptomus vicinus from Lake Buhi and the dominance of A. dorsalis in the pelagic plankton community of freshwater ecosystems. It would seem that A. dorsalis invasions in this area are more successful in inter-connected larger freshwater ecosystems. Keywords—Zooplankton, copepods, non-indigenous zooplankton, biological invasion, tropical lakes *Corresponding Author Email Address: ericrizo_99@yahoo.com Submitted: December 17, 2014 Revised: February 19, 2015 Accepted: February 20, 2015 Published: April 27, 2015 Editor-in-charge: Eduardo A. Padlan ____________________________________________________________________________________________________________ www.philscitech.org ARTICLE International Journal of Philippine Science and Technology, Vol. 01, No. 1, 2015 28