(eerie music)
[Daren Horton] People just love Caddo Lake. Caddo Lake gets
in your blood. It’s like a prehistoric environment with the bald Cyprus trees and the Spanish
Moss hanging down. It’s beautiful and people love it. When it’s under attack like this,
it really alarms people. This is a wetland of international significance and we’re
involved in a desperate fight to save it from this most aggressive plant in the world.
[Tim Bister] Giant salvinia is a threat to Caddo Lake.
(Boat motor starts) (Intense music)
[Tim] I’m Tim Bister and I’m a fisheries biologist
for Texas Parks and Wildlife. Caddo Lake is known as the only natural lake in Texas so
it is one of our gems that we really want to be able to protect.
Giant salvinia is a floating aquatic fern from South America.
It grows very rapidly it can actually double in size in 4 to 7 days.
Giant salvinia first showed up in Caddo Lake in 2006 on the Louisiana side at one of the boat ramps.
The worst year that we’ve had there was about 6000 acres of giant salvinia covering the Texas side of Caddo Lake.
That’s about half of the water that we have.
There were areas that were so completely covered by giant salvinia and the
plants growing on top of the salvinia mats, that it looked like dry land.
[Tim] The main river channel that travels through
Caddo Lake was completely covered by giant salvinia. There were many areas that you couldn’t
get a boat through. There were lots of people that were very concerned about the lake and
it was a year that growth was so bad that there just wasn’t a lot that could be done.
[John Findeisen] You can see where they sprayed. Lots of dead.
Dead is good.
[John] I’m John Findeisen. I’m an aquatic invasive
species biologist.
[John] This is an area where we sprayed. State contractors
had come in here and done some herbicide treatments on this and really pushed the salvinia back.
We’re using a combination of both the systemic herbicide that will circulate throughout the
plant as well as the contact herbicide that just burns wherever it touches. It’s still
slowly slowly dying, falling out, what green plant is alive our contractors are coming
in and spraying.
[Tim] The best strategy for invasive species management
is using an integrated approach. Using as many tools in your tool box to control a situation.
(Hose spraying)
[John] We’ve been using a combination of herbicides
recently with great success in the management of this species and being able to maintain the open water.
[John] In addition to that we’ve been trying for
well over a decade now of using biocontrol.
The giant salvinia weevil. It’s a species specific weevil, just feeds on giant salvinia and can control it.
We’ve seen control out here in several places. Parks and Wildlife raises and releases their own weevils, but we really
need a lot of people doing that and here recently the Caddo Biocontrol Alliance has stepped
up in releasing large numbers of weevils to help with this control.
[Daren Horton] We are in Uncertain Texas, at Caddo Lake.
What we are doing is raising giant salvinia weevils to control the giant salvinia plant.
The invasive aquatic plant that is trying to take over Caddo Lake.
[Daren] We wanted to build this greenhouse, mass produce
these weevils and get them out on the water in as large numbers as we can.
We're weevil ranchers.
DAREN These are the tanks where we grow the giant
salvinia. We introduce the weevils onto the salvinia here in a controlled environment,
we raise em. When the population gets to the right level we actually take the salvinia
from here, put it into totes, go
out to where the giant salvinia is and release these weevils into the environment.
It’s hot, hard work. This greenhouse in
the summertime is extremely hot. And Texas summers the temperature gets over 100 degrees.
It takes people who really love the environment and love the lake and love the area to give
so much time and work and effort and sweat to protect the lake.
(Rake splashing)
(Mellow Music)
[Daren] Morning, how y’all doing?
[Ted Barrow] All these are going on the pontoon, right?
[John] A lot of those people are the local people
who live and utilize the lake out here. They care because they live out here. They’re
out here everyday. And this is their home. They pour their heart and soul into managing
this salvinia in the lake to keep it from taking over.
(Bird whistles)
[Angler] Oh it’s beautiful. And the water since the
salvinia has died the water is perfect all over the lake to fish. It’s a great place.
It’s a magical lake, isn’t it?
[John] I think the future of Caddo is bright. I think
people are going to be able to enjoy the lake like they always did. Like the good old days
they talked about.
[John] It's extremely brittle but something was eating on it. We are seeing evidence of a moth larva or the weevil damage itself.
[Tim] It is frustrating having an invasive species that just won’t go away. Knowing that no
matter what we do, we’re never going to get rid of the giant salvinia at Caddo Lake.
But I do have the hope that our efforts are going to help continue to keep boaters having
the ability to get around the lake. To have anglers still have their places that they
like to fish. Native plants will come back. Fish will be able to use more of the lake.
Ducks will have open water to land on. It’s all tied together.