Ka Wai Ola - Office of Hawaiian Affairs, Volume 14, Number 4, 1 April 1997 — Apple Snail study stirs up controversy [ARTICLE+ILLUSTRATION]

Apple Snail study stirs up controversy

Last November, the Ka Wai Ola o OHA ran a story about apple snails that sparked some debate in the taro-growing community. The story tocused on a University ot Hawai'i Sea Grant Extension Service study ot apple snails intesting Hawai'i's wetland taro lo'i. The study explores the marketability of

the apple snail as Hawaiian escargot to upscale restaurants. The apple snail, while a potential cash crop, is also an aquatic pest. In an hour's time, apple snails ean digest a taro lau (leaf) leaving only the ha (stem). The study explores ways of controlling the apple snail, and analyzes their potential as a crop. Since it was released, U.H. professors involved with the study have received a great deal of feedback from farmers and others in the taro industry. While there are some farmers who report success with the two-crop strategy, many feel strongly that its promotion could devastate HawaiM's taro industry. The apple snail (Pomaeea canaliculata) is native to South America and is found in the Philippines and Taiwan. According to Robert Cowie, a snail expert with Bishop Museum, the apple snail was introduced to Hawai'i in 1989 by farmers in Ke'anae, Maui. They planted apple snails in their lo'i hoping to raise them as a second crop. But, unlike other aquatic snails that feed on algae, the apple snail feeds on aquatic crops, making for a less than ideal twocrop system. Since then, apple snail infestations have become a problem on every island except Moloka'i. It is estimated that there are 98 million snails in Wailua Valley in Ke'anae. That's 13 snails per square foot. The apple snail is prolific. A "clutch" (pictured on page 6) eontains between 25 and 1 ,000 eggs, with an average of 200. A female lays a clutch every 10 days, and the eggs hatch in about 10 days. It takes a snail three to four months to reach reproductive maturity, and

they live between two and five years. The apple snail poses a major threat to aquatic vegetables like watercress, ung choy, and lotus as well. In the Philippines they are the number one rice pest.

Apple snails cause big problems for taro farmers, but some are making money off fhe aquatic pest.