Giant Salvinia on Caddo Lake

Efforts to control and eradicate giant salvinia at Caddo Lake have been successful, experts say.

MARSHALL — One Caddo Lake pest seems to be under control, while another is creeping into the area, but the bass fishing’s fine, the audience was told this past week at a series of “State of the Lake” meetings.

The Caddo Lake Institute offered a series of three meetings — in Marshall, Karnack and Jefferson — to provide information on all things pertinent to the preservation and recreation of the natural body of water.

Tuesday’s one-hour session in Marshall spilled into overtime as experts and representatives from nonprofit groups gave updates and took questions on how their groups help maintain the lake.

“There’s not really anybody in charge of the lake,” said Laura Ashley Overdyke, Caddo Lake Institute executive director, noting that it’s not managed by U.S. Army Corps of Engineers, who has authority over Lake O’ the Pines. “So it’s a matter of Texas Parks and Wildlife, game wardens and then the local people.”

The nonprofit institute has been involved since 1992, providing scientific information to help the community make informed decisions when it comes to protecting Caddo Lake and its ecosystems.

John Findeisen, invasive species biologist with Texas Parks and Wildlife, spoke on TPWD’s management of giant salvinia with the use of herbicides and giant salvinia weevils.

Findeisen said that TPWD’s number of weevil releases into Caddo Lake has decreased tremendously, starting with a total of 35,900 weevils in 2014; 130,000 in 2015; 257,200 in 2017; 36,300 in 2017; to 5,000 in 2018.

“You can see that number began to increase, and — all of a sudden — it decreased in 2017 and 2018,” he said.

He said the drop is a reflection of Caddo Biocontrol Alliance, which owns and operates a climate-controlled weevil greenhouse to raise and release weevils to fight giant salvinia.

“They’re able to provide enough weevils (for) Caddo Lake that we can take our weevils and distribute elsewhere,” Findeisen said, noting TPWD has 17 other reservoirs fighting giant salvinia.

Findeisen cited success at Pine Island Pond.

“In 2015, Pine Island Pond was completely covered with salvinia,” he said. “We went in; we did not treat any of this with herbicides. The contractors didn’t treat it. It was just weevil release. By October of 2016, we were starting to see open water.”

A floating boom was added because of salvinia on the outer edges, but by April 2018, the waterway was completely open, he said.

“To this day, that remains open. We do have the contractors come in and do some herbicide treatments. I think they come in four or five times a year, and that’s it,” he said.

Vanessa Neace, area biologist at Caddo Lake Wildlife Management Area, told the audience about another invasive species — the emerald ash borer.

“Emerald ash borer is a nonnative invasive beetle,” she said, noting it kills all species of ash trees.

The bug is native to Asia and arrived in the United States via shipping crates and materials.

“The Texas Forest Service has been monitoring this beetle since 2012,” she said, noting it was first identified in Michigan in 2002 and first detected in Texas in Harrison County in 2016.

In July 2018, the bug was found in traps in Marion and Cass counties.

“This past June, they found this bug in two traps in the wildlife management area, not only on our east side but also on our west side,” Neace said.

She said more evidence of the beetle was found just this Monday as they scraped the bark off one of the trees.

“One of the biggest ways that it moves around the area is that it moves with firewood,” Neace said. “This little bug is responsible for the death of over 900 million trees. It started in Michigan; it’s gone all over the Northeast Coast, Texas, one location in Colorado. So it has killed millions and millions of trees.”

The audience also heard from Parks and Wildlife fishing biologist Tim Bister, whose job is to improve the quality of fishing.

“We do population surveys. We also do different netting surveys — trap netting, field netting. Another thing we do is we talk to anglers, see what fish they’re fishing for, how long they’re fishing so we can estimate the total hours fished by anglers throughout the year and calculate how long it takes them to catch a fish they’re trying to catch,” Bister said.

Survey results from 2017-18 shows bass as the premier species for the lake, he said.

“This year, Bassmaster Magazine named Caddo Lake one of the top 100 best bass lakes in the country,” Bister said.