Dr. Rob Dillon, Coordinator

Friday, July 25, 2003

Leptoxis plicata Release

To the FWGNA Group,

As many of you are aware, Paul Johnson (current chairman of the FMCS Gastropod Committee) has been working for several years to artificially propagate Leptoxis plicata, the federally endangered pleurocerid snail endemic to Alabama's Black Warrior drainage. Earlier this week he wrote to inform us of the successful release of almost 5,000 yearlings back to the wild. He suggests that this may be the first release of an artificially cultured endangered freshwater snail in the United States. I think it may be the first anywhere in the world, ever. Congratulations, Paul!

Paul sent us an article from the Sunday edition of the Birmingham (AL) News which offers a pretty good overview of the project and is mostly accurate. [Paul's notations are in brackets.] We join him in thanking Paul Hartfield of the USFWS and Stan Cook of AL-DCNR for making this small but important step possible.

Keep the faith!

---------[Birmingham News 07/20/03]----------

At a Snail's Place
Scientists release critters to breed in Locust Fork
JERRY BAKER News staff writer

Hoping to reverse a trend that began decades ago, research scientists released 4,876 snails Saturday into the Locust Fork of the Black Warrior River near Kimberly. It was the first of five annual releases planned in hopes of restoring the population of a federally endangered species. Though small, the plicate rocksnail is a cornerstone species upon which all the other animals living in the river depend, said Paul Johnson, a research scientist with the Tennessee Aquarium Research Institute. The snail lives beneath large, flat rocks and eats algae and organic matter; it is food for turtles and fish.

Sixty years ago, the half-inch-long snail was so plentiful in the Locust Fork that a person standing anywhere in the river's shoals would have a couple dozen snails under each foot, Johnson said. Now those snails are almost gone, victims of pollution and sediment washed into the river. Once found along the entire length of the river, their numbers have diminished so much that they are found in only a few shoals along a 20-mile stretch between Interstate 65 and U.S. 78, about 2 percent of their original habitat.

Johnson and several assistants carried the snails to the river in three one-gallon buckets in a cooler. He let the buckets sit for a while in shallow water to adjust their water temperature, then sprinkled the snails in an area where the water was a couple of inches deep. The released snails are the offspring of 100 he collected from the river in March 2002 from shoals near Sayre. Saturday's release is a result of five years of research and development, Johnson said. "This is aimed at trying to develop the techniques for restoring freshwater snails, especially in the Mobile River Basin," Johnson said. The Warrior River is a part of the Mobile River Basin. The basin is one of the most biodiverse in the world, Johnson said. It also is one of the most troubled. Of the 60 species of freshwater snails that have become extinct in North America, 42 of them are from the Mobile River Basin.

Eleven snail species are listed by the U.S. Fish and Wildlife Service as threatened or endangered, and eight of them are from the Mobile River Basin, he said [clarification - 11 listed species in AL only]. Sediment from development and strip mining along the rivers has washed into the streams and covered up the snails' habitat. Pesticides and herbicides also have contributed to snails' dwindling numbers, he said. The release site near Kimberly was chosen because Johnson said he knows snails can survive there. He found one snail after a couple of hours of searching a couple of months ago but came across none in a search last week.

Johnson will visit the river several times a year to monitor the snails. Each is marked with a one-millimeter tag affixed with dental cement, he said. The tags help researchers monitor the progress of the snails and ensure the same ones won't be used for breeding stock every time [clarification - adult broodstock was tagged, not the juveniles]. This fall he will release the 97 survivors of the original 100 he removed last year as breeding stock. He will put those back where they came from near Sayre [error - this was completed last year, and no adult mortality has been associated with 2003 propagation efforts].

Johnson plans to collect more each spring, and later in the summer he will release more. Johnson hopes to improve his technique so that about 10,000 1-and 2-year-old snails will be released each summer.

With conditions along the river improving, Johnson hopes his repopulation efforts will give the snail the boost it needs to survive. "They can take themselves out from the brink of extinction," Johnson said. "We've just got to give them a chance.