By Jan TenBruggencate
Advertiser Science Writer
LIHU‘E, Kaua‘i — A tiny snail unique to Kaua‘i has been placed on the federal endangered species list, and the U.S. Fish and Wildlife Service is looking for help in determining its critical habitat.
The Newcomb’s snail, known to science as Erinna newcombi, is found in small tributaries of six streams and rivers in the northern half of the island.
The black-shelled snail has no known Hawaiian name. It is just a quarter of an inch long and gained notoriety when its existence in the Makaleha Stream stopped a county water project there.
The snails live on submerged rocks, where they feed on algae. Their eggs are attached to rocks and vegetation, and unlike many other Hawaiian stream dwellers, they have no planktonic stage during which the creatures live in the ocean.
Newcomb’s snails are found generally at elevations of about 1,000 feet in small feeder streams of the Kalalau, Lumaha‘i, Hanalei, Waipahe‘e, Makaleha and the north Wailua waterways.
They may once have been in several other north Kaua‘i streams, but aren’t found there any longer for reasons not fully understood.
Scientists say there are numerous threats facing these little creatures today that weren’t there when they evolved into a unique species.
They are at risk of being eaten by introduced frogs and swordtail fish, and by the cannibal snail, Euglandina rosea, that was brought to Hawai‘i in hopes it would control the African snail. The same cannibal snail attacks Hawai‘i’s treasured and endangered tree snails.
The Newcomb’s snail is also at risk from two introduced marsh flies that attack eggs and adults. These flies were imported to control a non-native snail that carried a parasite of cattle.
Habitat destruction, both by humans and catastrophic storms and landslides, are further risks.
Most of the places where the snail is still found are high in the mountains, away from most human development.
The Fish and Wildlife Service is asking anyone with information about the snail to contact the service as it works on determining whether and what areas should be named as the snail’s critical habitat. That is the area the snail needs to recover from being endangered.
The service is asking for comments by March 30.
Once the service decides on critical habitat, it may hold a public hearing to seek further comment.
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