The species in question is undoubtedly Pomacea, the Apple snail.  Robert
Cowie at Bishop Museum has been doing a lot of work with these in
Hawaii, Philippines and Thailand.  They eat taro in Hawaii and rice
plants in the Philippines and Thailand.  In Hawaii they came primarily
from shells introduced as aquarium shells to clean the aquaria.  They
spred very rapidly.  They are sold in the fish market, and people keep
proposing that they be granted permission to grow them as an aquaculture
project.  A number of people have grown them, and inevitably, they
escape during some disastor or problem.
--
                     Aloha from Wesley M. Thorsson
Editor of Internet Hawaiian Shell News, a monthly Internet Publication
           122 Waialeale St, Honolulu, HI  96825-2020,  U.S.A
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