Expanding on the theme of my post last month, this morning's newspaper carried an Associated Press article with the following headline: "Snails Threaten Georgia Wetlands." Georgia DNR is reporting the discovery of a reproducing population of invasive Pomacea in ponds and streams of the Alabaha River system, a tributary of the Satilla in SE Georgia. Although not actually in the drainage of the Okefenokee Swamp, officials are concerned that the snail might be spread 20 miles south to the Swamp and cause significant environmental damage. A press release from the Georgia DNR-Wildlife Resources Division (upon which the AP article was based) is appended below.
The article refers to Pomacea as the "channeled apple snail," which is a good, descriptive common name. Elsewhere in the world the critter is more commonly called the "golden apple snail," because (at least initially) many of the populations were albinistic. The snail has become a terrible pest in Hawaii and throughout east Asia where rice and taro are grown. Breeding populations have also become established in Florida, Texas, and California. I've appended a few web references below the Georgia DNR article if you'd like to learn more.
Meanwhile, we here in Charleston are once again manning the southern breastworks. First Sherman and now this. Perhaps we'll have a bit more time to prepare for this invasion than the last.
Ga Wildlife Resources Division News Story
BLACKSHEAR, Ga. (9/13/2005)
Invasive South American Snails Breeding in South Georgia
It’s just the kind of tourism Georgia doesn't need. Recent surveys conducted by the Georgia Department of Natural Resources, Wildlife Resources Division (WRD) have documented breeding populations of a large, invasive species of snail native to South America. During a recent search, WRD biologists removed 79 of the channeled apple snails and 151 egg masses from a pond in Pierce County in a span of less than four hours.
A live snail found near the Alabaha River in Pierce County in early 2005 was identified as a channeled apple snail. The specimen was the first of its kind discovered in the state. Since then, live apple snails and eggs have been found in several ponds and streams in the Alabaha River system, a tributary of the Satilla River in Southeast Georgia.
"These snails have a voracious appetite for aquatic plants, which many native species depend on for foraging and shelter," said WRD Wildlife Biologist Brett Albanese. Shells of channeled apple snails can reach a width of more than two inches and a height of three inches, and are yellowish to brown in color. Channeled apple snails have established populations in at least six Florida counties, and breeding populations of the species also exist in Texas, California and Hawaii.
Initial findings of the snails in Georgia raised speculation that the specimens might have been aquarium pets released into the wild, but the subsequent discovery of a large population in a popular fishing spot may indicate otherwise. "We now suspect that these snails may have hitched a ride into Georgia on a fishing boat that had been in Florida waters, where the apple snail has also been introduced," said WRD Fisheries Technician Chad Sexton.
The discoveries were of particular interest to biologists because of the invasive nature of the species. An array of problems can arise when pet owners or fishermen introduce non-native species into Georgia’s waters. Non-native or nuisance species can be spread when anglers release live bait into the water or move between water bodies without cleaning boats and trailers.
The WRD Fisheries Management Section and the WRD Nongame Wildlife and Natural Heritage Section have been working to monitor the spread of apple snails in the Alabaha River system. They are experimenting with trapping and manually harvesting adult snails from ponds and streams and manually removing the egg masses from trees. "Although the track record for eradicating non-native species is not promising, biologists hope that they can halt or slow the spread of these snails in South Georgia," Albanese said. "One reason for optimism is that we can target two life stages of the snails both the eggs and the adults for removal."
Conservation agencies nationwide are working to stop the spread of non-native aquatic plants and animals, citing concerns about the potentially harmful impact to native species. "The wrong organism in the wrong place can eat or out-compete native species, which can have serious impacts on an entire aquatic community. Invaders can also spread non-native diseases," Sexton said.
For more information about aquatic nuisance species, visit http://www.protectyourwaters.net/ or http://www.gofishgeorgia.com/. Additional information on identifying apple snails is available at http://www.applesnail.net/. Georgia residents who think they have found an apple snail should collect it, photograph it and provide detailed locality information to WRD Fisheries Management in Waycross at (912) 285-6094, or WRD Headquarters at (770) 918-6400. Citizens should also be on the lookout for the apple snail’s bright pink eggs, which are laid on trees and shrubs above the waterline.
On-line Pomacea References:
- In addition to his site for hobbyists, Stijn Ghesquiere runs a nice website devoted to Pomacea as pests: http://pestalert.applesnail.net/ Hit the "ICMAM7" link for a good worldwide roundup of Pomacea problems, including a thorough US 2002 review by Howells & Smith.
- Here's a 2003 Article by Bob Howells in the Aquatic Nuisance Species Digest: http://www.anstaskforce.gov/ANS%20Vol%205%20No%201.pdf
- A recent review of the Golden Apple Snail in east Asia: http://www.fftc.agnet.org/library/abstract/eb540.html
To the FWGNA group:
Our thanks are due to Bob Howells for the update on Texas Pomacea copied below. Bob has also sent me three nicely-produced fliers on the subject, which are now available for download from the FWGNA site.
Bob is most smitten by recent DNA evidence suggesting that his Texas Pomacea are not true P. canaliculata, as have been introduced throughout the Pacific, but rather something else. Given the ease with which these animals can be cultured, however, I think it would be a shame to jump to such a conclusion without controlled breeding experiments. I understand that TX/HI Pomacea crosses are next on Ken Hayes' to-do list. Right, Ken?
Keep in touch!
Subject: RE: Pomacea in Georgia
Date: Mon, 19 Sep 2005 08:32:37 -0500
From: "Robert Howells" Robert.Howells@tpwd.state.tx.us
To: "Rob Dillon" email@example.com
Thanks for the heads up on the most recent applesnail information. There are a few points of interest. (1) We (TPWD/USDA/etc.) heard about the first Pomacea collections in Georgia last Spring…literally during a USDA applesnail meeting being held at that time in Houston. However, additional specimens have turned up in Georgia more recently. (2) Rob Cowie and his associates have determined that the large channeled Pomacea we have in the U.S. (those tested so far…) are not true P. canaliculata like those in Hawaii and in the Philippines. (3) The ANSD article was rewritten extensively by the editor and without my knowledge or approval. It contains some completely false information. Never cite it!!!! (4) I have gotten together with Alex Karatayev and Lyubov Burlakova (SFASU) and Romi Burks and one of her students (SWU) and drafted a chapter for a book by Ravi Joshi on Ampullariidae. We have addressed all the species of Ampullariidae in North America (there was actually a Canadian introduction a while back). Joshi expected the book out sometime this fall. Our chapter has a lot of photographs and range maps as well as a lot of new information on Texas populations being generated by the academic folks in Texas. (5) Attached are some handouts related to Pomacea in Texas that update status and terminology.
Howells, R. G. (2005) Exotic Applesnails in Texas Waters [PDF]
Howells, R. G. (2005) Invasive Applesnails in Texas: Status of these harmful snails through spring 2005 [PDF]
Howells, R. G. (2005) Channeled Applesnails: Recommendations to Prevent Their Spread [PDF]