A recovery plan that identifies actions to restore populations of the threatened combs 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 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 combs 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 combs 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 combs snails are present.
Unlike the other native freshwater snails, combs 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 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 combs 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.
comb'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 http://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.
The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 95-million- acre National Wildlife Refuge System, which encompasses 545 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 69 national fish hatcheries, 64 fishery resources offices, and 81 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign and Native American Tribal governments with their conservation efforts. It also oversees the Federal Assistance program, which distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to State fish and wildlife agencies.
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