Slowing The Snail Invasion

Volunteers are trying to slow a snail invasion. Dozens of volunteers swept through Langan Park this morning, 10/3/09, looking for apple snails. The invasive species is multiplying throughout the area. Organizers were using paint scrapers to collect as many snails and eggs from around the park as they could. The fist-sized buggers are then buried in dry ice. Organizers say the snails are a big problem.

“You have to get involved in this because if these snails get into the Mobile Bay Delta they could ravage the delta all the grass beds, which could impact our fisheries, our shrimp season, everything” says Mobile Baykeeper Executive Director Casi Callaway. Callaway says volunteers will be at it again next weekend. Officials believe someone dumped out their aquarium into the park a few years ago, inadvertently starting the snail crisis.

Here's a FAQ e-mail I was sent from officials on the snails:

1. What is an island apple snail? Island apple snails are mollusks that are native to Central and South America. They have been in the United States since 1950, but were not considered problematic until they began to feed on agricultural rice in Texas and Louisiana. Once apple snails were discovered to be damaging as a crop pest, they also became a concern in wetland areas where they were observed degrading native aquatic vegetation. The spiral shell of the island apple snail can vary in color from nearly black to a pale yellow and they can grow to over four inches in diameter. This species of snail reproduces by laying clutches of eggs during the warmer months of the year. The egg clutches have a pink bubble gum color.

2. Where can we find apple snails in the Mobile area? You can find them in Langan Municipal Park Lake and in portions of Threemile Creek.

3. If they are not native to this area, how did island apple snails get here? It is believed that the local population of island apple snails originated from releases of aquarium pets. By state regulation, it is unlawful to intentionally stock or release any fish, mussel, snail, crayfish or their embryos into the public waters of Alabama except back into waters from which they came without written authorization from Wildlife and Freshwater Fisheries Division of the Alabama Department of Conservation and Natural Resources.

4. Why should we be concerned about island apple snails? Apple snails have proven to be invasive species with the capacity to cause severe damage to native wildlife habitats and agricultural crops. In addition to damaging agricultural and wetland areas, apple snails can typically carry parasites that have potential for human health risks.

5. What do ADCNR and the U.S. Fish and Wildlife Service plan to do about the island apple snails in Langan Municipal Park Lake and Threemile Creek? In an effort to control the population of island apple snails, biologists are using an EPA-approved chemical treatment called copper sulfate to kill adult and juvenile snails. Besides being an effective molluscicide, copper sulfate is a material that has historically been used to control algae in swimming pools and fish ponds. The copper sulfate that will be used is also approved for use in potable water supply lakes. A series of chemical treatments will need to be made, in addition to the removal and destruction of snail eggs.

6. How will the copper sulfate affect other wildlife? Copper sulfate is not toxic to mammals, birds, or reptiles. But they can be toxic to fish.

7. Could there be a fish kill? There is a chance of a fish kill in Langan Municipal Park Lake and Threemile Creek. If a fish kill does occur, biologists are prepared to restock the lake to be as good as, if not better than before the chemical treatment.

8. Why is it so important to get this population of island apple snails under control so quickly? The island snails are quickly multiplying. The population needs to be under control before it invades the Mobile-Tensaw Delta.

9. How long will it take to kill them all? We don’t expect that this initial effort will completely eradicate the apple snails from Langan Park or Threemile Creek. A long term monitoring and control program will be needed to successfully keep this species from expanding its range in Alabama and threatening other aquatic habitats.

10. How do I get more information on Island Apple Snails? Contact WFF Biologist Ben Ricks at (251) 626-5153 or by e-mail at ben.ricks@dcnr.alabama.gov. You can also contact USFWS biologist Andy Ford at (251) 441-5838 or by e-mail anthony_ford@fws.gov.