SAN ANTONIO – They are small, but they are a huge threat to the San Antonio River ecosystem: Apple snails.
The creatures invaded the river and several were pulled out of the water during early January’s River Walk draining.
The Apple snails are native to South America and can grow up to six inches.
According to biologists with the San Antonio River Authority (SARA), the snails are voracious eaters and eat any sort of native aquatic plants. They were also outcompeting the snails native to Texas.
“The aquatic plants are vital to the food web. They create a nursery habit for fish so they are super important for the total assemblage,” said Chris Vaughn, lead aquatic biologist with the San Antonio River Authority.
San Antonio River Authority officials discovered the presence of the Apple snails in October.
Their presence is often indicated by bright pink egg sacks that can contain thousands of individual eggs.
River Authority staff removed 79 egg sacks from the River Walk on Oct. 31.
During this month’s draining, River Authority officials found and removed 105 Apple snails and will continue to monitor their presence.
Their journey to the San Antonio River was not that complicated.
“You can readily find these at a PetSmart or Petco so somebody almost definitely bought it for their aquarium, it got too big so they dumped it into the river,” said Vaughn.
Apple snails were not the only species or items removed from the river.
SARA’s Environmental Science team dispatched 1,460 non-native species, including 355 plecostomus (suckermouth catfish) and 401 tilapia.
River authority staff collected a total of 24 scooters in the Museum Reach area.
SARA staff completed work around Pearl stage area to support aquatic plantings in the future.