SAN ANTONIO – The San Antonio River Authority is increasing its efforts to remove invasive apple snails from the San Antonio River, where the fast-reproducing species has threatened the river’s ecosystem and spread by the thousands.
Apple snails are native to South America, but they have been found in growing numbers on the San Antonio River.
The river authority has worked since 2019 to remove the snails and their egg clusters, which can often be spotted on river walls and look similar to bright pink bubble gum.
The river authority said that over the past seven years, crews have removed nearly 43,000 adult snails and more than 118,000 egg clusters.
“They can lay anywhere from 500 to 2,000 eggs every 10 to 14 days,” said Adrian Arroyos, an aquatic biologist with the San Antonio River Authority.
Arroyos said he believes the invasion may have started when someone dumped an aquarium containing at least one apple snail into the river.
“With no natural predator, that makes their spread pretty easy,” Arroyos said.
To help slow the species’ population, the river authority launched two pilot programs at the start of the year.
“We’re attacking them based on frequency, but we’re also trying to disrupt their reproductive strategy,” Arroyos said.
One effort sends crews and volunteers onto the river in kayaks to scrape off egg clusters and remove adult snails when possible. The river authority initially sent teams out every 14 days, but officials found that they were still being outpaced by the snails’ reproductive cycle.
“We changed up the frequency this year to every 10 days,” Arroyos said.
Under the water, the river authority is also testing two types of barriers as part of the pilot effort.
“In a year on materials, probably anywhere from $2,500, we try to keep it as low cost as possible,” said Arroyos. “Obviously, the money that we get is taxpayer-based, so we want to make sure we’re managing our resources properly. And that’s exactly why we also did a pilot project first.”
The river authority plans to collect and review data at the end of the year to determine whether the pilot programs are working.
Officials are also reminding residents not to dump aquariums or aquatic pets into local waterways.
The San Antonio River Authority has partnered with several pet shops that will take unwanted tanks and the animals inside free of charge. Those pet shops include Papa Jim’s Tropical Fish, Texas Tropical and Marine and Elegant Reef Tropical Fish Studio.