The City of Austin is taking steps to manage the spread of hydrilla in Lake Austin. This non-native, invasive plant has been increasing, particularly in coves and backwaters downstream of Loop 360. A recent survey by Texas Parks and Wildlife found hydrilla in 74 acres, which is about five percent of the lake.
To address this issue, the city plans to introduce approximately 350 sterile grass carp into Lake Austin later this week. The stocking rate will be about five grass carp per acre of hydrilla. Grass carp are known to feed on hydrilla.
Hydrilla can benefit fish and water quality but can also grow rapidly, becoming problematic for both the environment and community. Managing its growth requires a careful approach.
Originating from Asia, hydrilla was introduced to the United States in the 1960s and first appeared in Lake Austin in 1999. It covered nearly a third of the lake at its peak in 2012 and 2013. The city’s goal is to slow down its growth without negatively impacting the lake’s environment.
Currently, hydrilla does not affect overall lake use, with other vegetation like Eurasian watermilfoil remaining dominant. Grass carp prefer eating hydrilla over these plants.
Residents and visitors are encouraged to help prevent spreading non-native species by cleaning boats and gear before and after use, avoiding dense patches of underwater vegetation while swimming or boating, and not tossing plant pieces back into the lake as state fines can reach up to $2,000 per plant.
For more information on hydrilla and plant life in Austin’s lakes, visit AustinTexas.gov/Watershed.
The City of Austin Watershed Protection Department works to protect lives, property, and the environment by reducing flooding impact erosion and water pollution effects.
