Hawaii's snails and slugs are not wanted on mainland


POSTED: Tuesday, August 18, 2009

Hawaii has snail and slug pests that the mainland wants to keep out to protect agriculture and the environment, a University of Hawaii-Manoa researcher says.

They include African snails, apple snails and Parmarion martensi, a slug implicated in rat lungworm disease, said Robert Cowie, a snail/slug biologist.

Cowie, of the Center for Conservation Research and Training, Pacific Biosciences Research Center, led a team that developed the first list of non-native snails and slugs of national quarantine significance.

The study was focused on species that are not already in the United States or are only locally distributed, he said. Hawaii was included because it has species the mainland is concerned about getting, he said in an interview.

“;Hawaii is sort of a special case,”; said Cowie, chairman of the Ecology, Evolution and Conservation Biology graduate program at UH-Manoa. He said the group decided that even if some snail and slug species were widely distributed in Hawaii, “;We would still consider that a problem for import into the mainland U.S. because theoretically it is impossible to confine those species to the Hawaiian Islands.”;

Cowie said apple snails have been introduced to the mainland but are not in particularly sensitive areas. The one here causing major taro problems is in small areas of California and Arizona, he said. “;What we don't want to happen is for it to get into California rice fields.”;

In the mid-1990s, he said, the California and Arizona agriculture departments asked him to identify some tiny snails found on shipments from a Puna nursery. “;It was something we hadn't seen in Hawaii before.”;

He said those shipments were destroyed, but as far as he knows, no exports from Hawaii's horticulture industry to the mainland or foreign countries have been prohibited because of snails and slugs.

The U.S. Department of Agriculture asked the American Malacological Society in 2002 to assemble a list of potentially threatening snail and slug pests because they are circulating around the world with globalization.

In the 1960s, African snails were introduced to Florida by a boy who took them home from Hawaii as pets in his pockets, Cowie said. He let them loose, which caused a huge infestation that took years and a lot of money to eradicate, he said.

Alien species in the United States cost an estimated $120 billion annually in damage to agriculture and the environment, the researchers reported.

The USDA asked them for a list of 15 species considered of highest priority to prevent them from entering or becoming established in the U.S., but they submitted a list of 48 species or groups of species representing 18 families.

Rather than restrict themselves, Cowie said they decided “;it was better to be a bit more inclusive, and at least that keeps people sufficiently aware of broader groups that might cause problems.”;

Top-ranked potential pests are Ampulariidae (freshwater apple snails), already in Hawaii, and a family of snails called Hygromiidae, not yet here. However, they are around the Mediterranean and southern Europe and could be imported with domestic tiles, Cowie said.

He said funding has been requested to organize a conference on rat lungworm disease, which has been reported on the Big Island and is increasingly prevalent because of the snail Parmarion martensi. It was only introduced about a decade ago but seems to be spreading, he said.

“;Even though it's in Hawaii, it's not on all islands,”; he said, stressing the importance of trying to prevent harmful snails and slugs from moving among islands.