A small army of volunteers in kayaks have made it their mission to seek out and remove a pesky non-native snail and its bubblegum-pink egg clusters along the San Antonio River.

Four years and thousands of removals later, the San Antonio River Authority has launched a new dashboard to keep track of the fight against the invasive apple snail waged by the volunteers and its own personnel.

The snails, native to South America, are a popular home aquarium species first found in the downtown San Antonio River in October 2019, likely due to an illegally dumped pet. The quickly reproducing snails, which are the size of a large apple and lay egg clusters that can contain up to 2,000 eggs, could negatively impact native species if they make their way further down the San Antonio River. The goal is to remove them along the River Walk whenever they are spotted.

“The big concern with apple snails is that they eat vegetation, and they’re quite adept at that,” said Shaun Donovan, the river authority’s manager of environmental sciences. “We’ve seen them start moving a little bit further downstream where in-stream vegetation is really important.”

The new dashboard, created by one of the river authority’s data specialists, launched two weeks ago with the aim of informing San Antonians how the ongoing fight against the snail is progressing.

Updated weekly, the dashboard features a color-coded map, answers to commonly asked questions about the snails and charts showing the snails’ seasonality and growth. It also includes photos of an egg clutch, adult snails and a link for how to help remove the snails.

The numbers on the left are cumulative since the river authority started removing snails.

“We want to make sure that the community is able to understand how it’s affecting their river,” said Paul Martinez, the dashboard’s creator. “We wanted to make sure we included a map so that folks can actually relate to where this is happening and to what parts of the river are being affected.”

Since the snails’ arrival, residents have often requested information from the river authority on the latest data about the snails, Donovan said.

Rather than sending data to everyone who asked for it, the river authority felt it was easier to make a dashboard that keeps up-to-date data about the apple snail.

According to the dashboard, the river authority and volunteers have removed more snails and their eggs from the downtown reach of the river than from the Museum Reach, King William Reach and Mission Reach.

Scraping parties — removing the snails and eggs where they were attached to the river’s retaining walls — became a regular activity for authority staff in early 2020, when it wasn’t clear yet how many apple snails were in the river, Donovan said.

But it soon became apparent to authority staff this was a bigger problem that would require more resources, he said. The authority hired a consultant to help manage the issue for a couple of years, Donovan said.

The authority then decided to train their “river warriors” — volunteers who pick up trash and pollution — to help remove the apple snails, he said. The river authority has roughly 115 volunteers trained to remove apple snails, said river authority spokeswoman Katye Brought.

Volunteers have removed more than 20% of all the apple snails harvested from the river.

“It is very evident in the visual product that Paul put together that the volunteer group is having a significantly increased impact from year to year,” Donovan said. “Just the sheer numbers are more than what our staff can do and what our consultant can do.”

While these volunteers remove snails and their sticky eggs regularly, Donovan and Brought both emphasized that residents should not try to remove the snails or egg clusters without training or professional help — else they risk accidentally helping the apple snail spread the eggs.

Residents who want to become trained to help can apply to become a river warrior through the river authority’s website, Brought said.

“We’re really excited to have this [new dashboard] as a permanent feature on our website,” Donovan said.

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Lindsey Carnett

Lindsey Carnett covers the environment, science and utilities for the San Antonio Report.