Invasive apple snails: ecology and management in Hong Kong
Apple snails in the genus Pomacea (Ampullariidae) invaded Hong Kong in the early 1980s. It is unknown how many species have been introduced into Hong Kong. A recent study has shown that only one species (Pomacea canaliculata) is present in the New Territories, yet it is not present in Hong Kong Island nor Lantau Island, the two largest islands with streams and abandoned rice paddies. In the New Territories, it is widely distributed in various freshwater habitats (ponds, drainage channels, semi-aquatic vegetable gardens, abandoned rice paddies, rivers and streams). Elsewhere in Asia, P. canaliculata is often a pest of rice, but in Hong Kong where most rice paddies have been abandoned, the first negative impact of P. canaliculata was reported by farmers who discovered that the snails devoured semi-aquatic vegetables, especially watercress (Nasturtium officinale) and water spinach (Ipomoea aquatica). In recent years, it has become clear that P. canaliculata could have reduced wetland biodiversity by grazing on macrophytes and by predation on benthic invertebrates, and altered wetland function by releasing nutrients into the water. It also has the potential to out-compete local macroinvertebrates because of its high secondary production. Apple snails in vegetable gardens are controlled by hand-picking, supplemented by application of chemicals, especially lime and tea seed cake. Those in constructed wetlands are controlled by hand-picking. A recent field study showed that black carp could be used to control apple snails in constructed wetlands.
Ampullariidae, biological control, grazing, macrophytes, Mollusca, nutrient, phytoplankton, Pomacea, secondary production
Source Publication Title
Biology and Management of Invasive Apple Snails
Ip, Kelvin K.L., and Jian-Wen Qiu. "Invasive apple snails: ecology and management in Hong Kong." Biology and Management of Invasive Apple Snails (2017): 145-166.