Golden Alga Surfacing, TPWD Steps Up Monitoring Efforts
USSFN: 2/02/05 - (Austin, TX) - Active golden alga blooms are causing fish kills in nearly a
dozen water bodies in north-central Texas, according to the Texas Parks and
Wildlife Department.
Most of the fish kills are relatively small and involve shad, an abundant
forage fish, but some game fish species are also being lost, say investigators
with TPWD’s Kills and Spills Team.
"We’re seeing more ongoing activity," said David Sager, Ecosystem/Habitat
Assessment branch chief at TPWD. "We’re monitoring and taking water samples,
studying the water chemistry and a lot of other parameters of the lakes during
the blooms to see if there’s anything we can attribute to the cause."
TPWD is currently monitoring golden alga activity on Lake Whitney, where cell
counts had been rising during the last two weeks and a fish kill occurred on
Sunday, Jan. 30 in the upper end of the lake.
"Unfortunately, it is happening, but we expected it because cell counts (the
density of the alga) were going up and the water was turning yellow and foamy,"
said Joan Glass, a Kills and Spills Team investigator.
Golden alga activity has been ongoing along the Brazos River watershed for
several weeks, impacting fisheries at Possum Kingdom Reservoir and Lake
Granbury. Because of recent rainfall, dams at both impoundments have been
releasing water, which Glass said may be contributing to activity at Lake
Whitney.
TPWD is also monitoring for golden alga on the following: Lake Kemp, Lake
Diversion, Lake Sweetwater, Lake Colorado City, Moss Creek Lake, Wadley-Barron
Park pond in Midland and Red Bluff Reservoir in New Mexico. E. V. Spence
Reservoir is not experiencing a kill and the Colorado River between Spence and
O.H. Ivie Reservoir is stable. There have been no reports of any dead or
stressed fishes in O.H. Ivie Reservoir.
Biologists at the Dundee State Fish Hatchery in Wichita Falls are also
experiencing golden alga in several hatchery ponds and are experimenting with
various techniques to control the alga. "They’re looking at various treatment
options including barley straw in containers to see if it helps control the
toxins," said Sager. "Straw has been used to control algae in other lakes and
areas, but it’s never been tried on golden alga."
While golden alga is present on several lakes, biologists say the good news
is that the blooms have not returned to Lake Texoma. Texas and Oklahoma
fisheries biologists have not found any high concentrations of the toxin
producing alga in samples taken throughout the lake.
Glass also reported that golden alga activity on Lake Granbury appears to be
subsiding. "We’re not losing any more fish and a fishing tournament was held
there over the weekend and they were catching fish so that’s a good sign," she
noted.
The ongoing algal blooms also are providing researchers with an active event
to study, according to Sager. "We’ve begun an intensive monitoring program at
Lake Whitney and will be taking samples of all the different plankton
communities. We’ll share that information with the universities so they can use
it in conjunction with their research."
Scientists from several universities in Texas are working in laboratories and
with net enclosures at Possum Kingdom Reservoir studying the affects of water
quality on algal bloom toxicity. Researchers are also looking at algae genetics.
Another study is focusing on the economic impacts of fish kills; specifically at
the 2001 golden alga fish kill events at Possum Kingdom Reservoir.
"We’re also working in cooperation with river authorities and local
governments to obtain water samples from around the state to see where golden
alga might be present," added Sager. "That could be helpful if we find it in
locations that aren’t experiencing kills. We could try to identify what controls
are present at those sites that aren’t present at sites experiencing fish
kills."
First discovered in Texas in 1985, golden alga (Prymnesium parvum)
was identified in a fish kill in the Pecos River and has since been responsible
for fish kills in the Colorado, Canadian, Wichita, Red and Brazos river systems
as well.
This alga releases a toxin that kills gill-breathing organisms such as fish
and clams. According to the Texas Department of State Health Services, anecdotal
evidence has shown no human health risks associated with golden alga.
Since 2001, golden alga fish kills have occurred on two dozen reservoirs in
Texas. Since 1985, nearly 18 million fish have been killed, most of which were
either forage or rough fish species.
Contact: Steve Lightfoot, (512)
389-4701,
steve.lightfoot@tpwd.state.tx.us Source:
Texas Parks and Wildlife Department |
