Massive invasion of Arctodiaptomus dorsalis (Copepoda, Calanoida, Diaptomidae) in Philippine lakes: a threat to Asian zooplankton biodiversity?

Abstract

A study originally intended to update the systematics and zoogeography of calanoid copepods in Philippine lakes has led to the discovery of an invasion by the Neotropical Arctodiaptomus dorsalis. It now occurs in 18 out of 27 lakes in the archipelago. Only four of the 12 previously recorded native and endemic calanoids have been encountered in the lakes, which may indicate that most have been displaced by A. dorsalis, although a general deterioration of water quality by fish culture may also have contributed to a suppression of the local fauna. Undescribed species may have been affected as well. A. dorsalis was first reported in the Philippines from Laguna de Bay in 1991, where it was said to have been introduced via ship drinking water reserves, but co-introduction with tilapia is more probable. Intensive aquaculture practices during the past 20 years have aided its dispersal to other areas and have provided environmental conditions that favor its survival. The rapid spread of A. dorsalis, paralleled by a loss of calanoid diversity in the Philippines, may repeat itself if this opportunistic species succeeds in spreading to mainland Asia

Effect of temperature on life history traits of the invasive calanoid copepod <i>Arctodiaptomus dorsalis</i> (Marsh, 1907) from Lake Taal, Philippines

“…Zooplankton was collected by performing four vertical net hauls using a conical plankton net (mesh size, 80 µm; mouth diameter, 30 cm) at a pelagic site (depth, 40 m) in Lake Taal, Philippines (14°00′40.6″N, 121°05′19.1″E), where A. dorsalis was previously documented (Papa et al 2012a, b). In addition, one liter each of lake water from depths of 0, 5, 10, 20, 30, and 40 m was collected with a water sampler and then combined for use as the culture medium.…”

“…Recent studies also showed that there has been a massive invasion of A. dorsalis in 18 out of 27 lakes investigated in the Philippines (Papa et al 2012a). Introduction of this spe-cies may have been through ship drinking water reserves dumped into Laguna de Bay (Tuyor & Baay 2001) which was then, through aquaculture practices, dispersed to other parts of the country (Papa et al 2012a). Recent studies by Metillo et al (2014) and Rizo et al (2015) added five more new locality records of A. dorsalis in the Bicol region of Luzon Island and Lake Lanao in Mindanao Island.…”

“…Arctodiaptomus dorsalis (Marsh, 1907), a neotropical species, is known for its propensity for transcontinental invasion (Papa et al 2012a). It was originally recorded to occur in the Americas, extending from the southern United States, through Central America, and to the north of South America (Reid 2007).…”

“…Detailed taxonomic studies on specimens collected from 2008 to 2010 revealed that it was actually A. dorsalis, and not T. vicinus (Papa et al 2012b). Recent studies also showed that there has been a massive invasion of A. dorsalis in 18 out of 27 lakes investigated in the Philippines (Papa et al 2012a). Introduction of this spe-cies may have been through ship drinking water reserves dumped into Laguna de Bay (Tuyor & Baay 2001) which was then, through aquaculture practices, dispersed to other parts of the country (Papa et al 2012a).…”

“…The aim of this study was to successfully culture A. dorsalis collected from Lake Taal, a large volcanic caldera (Ramos 2002) and the third largest lake in the Philippines (Hargrove 1991), at three different temperatures to evaluate the effects of temperature on life history parameters, such as post-embryonic development time, clutch size, and hatching success in this calanoid species. Anthropogenic activities, specifically aquaculture due to increasing food demand, can be attributed to Lake Taal s eutrophication (Vista et al 2006, White & San Diego-McGlone 2008, making conditions favorable for the thriving population of A. dorsalis (Reid 2007, Papa et al 2012a. This is also the first attempt to culture expatriate A. dorsalis outside of its original geographical distribution.…”