September 18, 2006
A recovery plan that identifies actions to restore populations
of the threatened Newcomb's snail, one of the few freshwater
snails native to Hawaii, was released today by the U.S. Fish and
Wildlife Service. Found only on the island of Kauai and numbering
approximately 6,000 to 7,000 individuals, this species is highly
susceptible to extinction given its small numbers and restricted
distribution. The plan focuses on actions that will maintain and
improve habitat and ensure that a single catastrophic event will
not eliminate large numbers of these unique animals.
A draft of the plan was released for public review and comment in
March 2004. After the 60-day review period, comments from the
public and scientific peer reviewers were considered and
incorporated into the final plan.
The plan contains detailed criteria needed to prevent the
extinction of the Newcomb's snail and ultimately recover the
species within its historic range. The Service recommends
conducting scientific research to increase knowledge about the
snail and its habitat needs, maintaining and improving habitat for
the snail by protecting water flows, conducting predation studies,
and working with governmental and private entities to protect and
restore snail habitat.
"Often our attention is focused on charismatic Hawaiian species
such as the nene and monk seal while the lesser known species
remain in relative obscurity," said Patrick Leonard, field
supervisor for the Pacific Islands Fish and Wildlife Office. "No
matter the size and appearance, each species plays a significant
role in preserving the biological and cultural integrity of
Hawaii. The Newcomb's snail is no exception and this plan will
help preserve the species and hopefully garner it much needed
attention and interest."
According to the recovery plan, the snail may be considered for
delisting if populations are stable or increasing through natural
production for a minimum of five consecutive years, and
populations are located in watersheds that are geographically
widely distributed throughout its range. Minimum flows must also
be designated and maintained for stream reaches where populations
of Newcomb's snails are present.
Unlike the other native freshwater snails, Newcomb's snail has
lost its shell spire resulting in a smooth, black shell formed by
a single oval whorl about a quarter-inch long. The snail feeds on
algae and other material growing on submerged rocks. Adults attach
their eggs to underwater rocks or vegetation, and their entire
life cycle is tied to the stream in which they live.
Restricted to 10 small sites (subpopulations) located along 6
streams in the interior of the island of Kauai, most snails limit
their individual range to a few square feet of a single
side-channel or single waterfall in the stream. As much as 90% of
the total population is restricted to just two of the 10 sites,
making them highly vulnerable to a single catastrophic event such
as a hurricane. The Newcomb's snail prefers natural springs
adjacent to streams.
Introduced, nonnative species and habitat destruction resulting
from the reduction or elimination of flows in streams and springs
are the primary threats to the snail's existence. Nonnative
predators vary from the rosy glandina snail and two species of
marsh flies to the green swordtail fish and the American bullfrog.
Newcomb's snail was listed as a threatened species on January 26,
2000. Critical habitat for the species was designated on August
20, 2002.
Availability of the recovery plan was announced in the Federal
Register on September 18, 2006. The recovery plan is available
online through the Fish and Wildlife Service's website at
www.fws.gov/pacific/pacificislands/.
Paper copies or a CD of the recovery plan may be requested by
calling the Fish and Wildlife Service's Honolulu office at 808 792
9400.
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