Snitch on the snails: Invasive species spotted in San Antonio River can lay up to 2,000 eggs

See a snail, report a snail.

The San Antonio River Authority needs water warriors to help report sightings of an invasive species.

Giant apple snails are an invasive species to Texas that grow up to six inches long. They can be seen in numerous bodies of water throughout Texas, including along the San Antonio River Walk.

Apple snail’s pink egg clutches are also easy to spot and semi-resemble a wad of chewing gum.

“Female apple snails lay weekly clutches containing between 500-1000 eggs once they reach maturity. Some can even lay up to 2,000 eggs,” according to a blog post from SARA.

The snails wreak havoc on aquatic vegetation and are known to carry a rat lungworm parasite that can infect humans, causing a type of meningitis, according to a Facebook post from Texas Parks and Wildlife. The parasite has yet to be found in Texas.

“Having the River Warriors out there on the water, as much as they have been, has been a tremendous help,” said Chris Vaughn, Senior Aquatic Biologist. “To date, River Warrior volunteers have removed 48 apple snails and 1,260 egg casings.”

Shaun Donovan, Environmental Science Manager for the San Antonio River Authority, previously told KSAT that the number of snails is “consistently getting worse.”

SARA officials found three to four times more adult snails in 2021 than the previous year. The number of egg cases SARA found in 2021 was more than double the amount they found in 2020.

“If we can get the egg cases out, it means that there’s not a stand of young individuals that are going to replace the older ones,” Donovan said. “The older ones (will) die out. So, it’s critically important for us to take the egg cases off as soon as we see them so that we’re not allowing for successful reproduction of the apple snails in the river.”

Apple snails are native to South America and were first spotted in the San Antonio river in Oct. 2019 along the Museum Reach portion.

Snitch on the snails! You can report any sighting of egg cases or adult apple snails by calling (866) 345-7272 or reporting it on the SARA website.

You can also become a true River Warrior volunteer with SARA.