SAN ANTONIO — The San Antonio River Authority launched two pilot programs at the start of 2026 to combat invasive apple snails in the San Antonio River. The agency increased the frequency of removal efforts from every 14 days to every 10 days and began testing underwater barriers.

One pilot program involves crews and volunteers using kayaks to scrape off egg clusters and remove adult snails. The San Antonio River Authority is testing two types of barriers underwater as part of the pilot effort. The River Authority's 2026 pilot program includes underwater barriers modeled after bird-deterrent spikes, a design previously tested in controlled environments for aquatic invasive species management.

Adrian Arroyos, an aquatic biologist with the authority, explained the strategic shift in removal tactics. "We’re attacking them based on frequency, but we’re also trying to disrupt their reproductive strategy," he said. Apple snail egg clusters are often found on river walls and resemble bright pink bubble gum.

Arroyos noted the high reproductive rate of the invasive species poses a persistent challenge. "They can lay anywhere from 500 to 2,000 eggs every 10 to 14 days," he said. The lack of natural enemies in the local ecosystem further accelerates their expansion. "With no natural predator, that makes their spread pretty easy," he said.

The San Antonio River Authority has worked to remove apple snails and their egg clusters from the San Antonio River since 2019. Over the past seven years, crews have removed nearly 43,000 adult apple snails and more than 118,000 egg clusters from the San Antonio River. Since coordinated removal efforts began in late April 2020, the San Antonio River Authority has removed 4,217 adult apple snails and 22,154 egg cases through its River Warriors volunteer program.

In 2025, crews removed 18,000 apple snail eggs through the River Authority's biennial river drainage process, compared to 11,212 adult snails removed in the same year. The San Antonio River Authority's River Warriors volunteer program, established in 2020, has trained 115 volunteers to remove apple snails. Arroyos stated that he believes the apple snail invasion may have begun when someone dumped an aquarium containing at least one apple snail into the river. Apple snails are native to South America.

The authority aims to maintain affordability while implementing these new measures. "In a year on materials, probably anywhere from $2,500, we try to keep it as low cost as possible," he said. The San Antonio River Authority was established in 1937.

The pilot programs represent a shift in strategy after years of manual removal efforts yielded tens of thousands of snails and egg clusters. By increasing removal frequency and testing physical barriers, the authority seeks to interrupt the reproductive cycle of a species that can lay up to 2,000 eggs every two weeks. The initiative builds on data from the River Warriors program and recent drainage operations that removed thousands of eggs in 2025.