Austin battles invasive lake species


by KRIS BETTS / KVUE News and photojournalist MATT OLSEN

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Posted on March 18, 2013 at 10:13 PM

Updated Monday, Mar 18 at 10:21 PM

LAKE AUSTIN -- It's responsible for half a million dollars worth of damage to Tom Miller dam, causes erratic driving as boats swerve to avoid it and was a major factor in at least one drowning in Lake Austin: It’s Hydrilla, and it’s worse than ever.

“Sometimes you can get tangled up in it and it'll scare you a little, because it feels like it's going to keep you from swimming and coming up above the water," said recreational fisherman Chris Summers.

Mary Gilroy with the City of Austin Watershed Protection Department said the problem starts in Lake Travis.

As water levels lower, Hydrilla spreads to Lake Austin.

“The water coming out of Lake Travis was much warmer than we were used to, and Hydrilla likes warmer water,” Gilroy said.

The most effective way to get rid of this growing invasive species is with a flood, but since that isn't happening anytime soon, the City of Austin is doing the next best thing by dumping fish into the lake that feed on Hydrilla.

Nine thousand Asian grass carp will be dumped into Lake Austin by the beginning of April.

“We're doing it early in the year, last year we didn't stock until June,” said Gilroy.

The City dumped 15,000 carp into the water in 2012 but "the fish we put into the lake last year were not able to keep up with the growth rate that Hydrilla was exhibiting,” Gilroy said.

This year, there are 588 acres of Hydrilla in the lake, and Gilroy said the City is looking to attack as soon as possible.

“We're hoping this year, by hitting the plants really hard and doing it early in the year, that we should be able to see some impact,” she said.

As of February, there were a total of 20,000 grass carp already in Lake Austin. The latest delivery of carp will be paid for by the City.