INTRODUCED DECAPOD CRUSTACEANS IN SINGAPORE'S RESERVOIRS

Introduced or alien freshwater decapod crustaceans from Singapore's reservoirs are documented from the results of an ongoing survey. Four species of decapods were recorded in the reservoirs, viz., one freshwater crayfish, Cherax quadricarinatus (Parastacidae) and three freshwater shrimps, Macrobrachium lanchesteri, M. nipponense, and M. aff. inflatum (Palaemonidae). Native decapods were not found in the actual reservoirs, but in forest stream inlets draining into the reservoirs. All four species were introduced through the ornamental pet trade, indicating the significance of this invasion pathway in Singapore. As yet, no ecological impacts on native ecosystems are known for these introduced species, although the possibility that they could be undergoing a lag phase or of more invasive alien decapods being introduced cannot be discounted.