Archived News Release
May 21, 2001
Golden Alga Wipes Out TPW Hatchery Striper Production
AUSTIN, Texas — Texas Parks and Wildlife fisheries biologists are racing against the clock to salvage this year's striped bass restocking efforts after golden algae toxins killed the state's entire hatchery production.
Officials at the Dundee State Fish Hatchery near Wichita Falls believe the same deadly toxins that resulted in fish kills on three Texas lakes along the Brazos River earlier this year were also responsible for wiping out the facility's striped and hybrid bass production. The fry from the 28 million striped bass eggs and 37 million hybrid bass eggs were lost because of exposure to the toxin.
According to Gary Saul, TPW hatcheries chief, biologists will try to collect female stripers that have not spawned yet in hopes of gathering enough fry to meet annual restocking schedules next month. "We're at the very end of the striper spawning run," he said, noting that the usual hatchery production process will have to be circumvented. "If we can collect enough females to pull off a spawn, we'll have to go with a straight fry stocking instead of allowing the fish to grow to fingerling size. Because the toxins are still present at Dundee, we can't risk using our hatchery grow-out ponds."
The need for replenishing striped bass stocks on some Texas reservoirs this summer was amplified with the occurrence of Prymnesium parvum, a species of golden algae that has impacted striper populations on Possum Kingdom Lake, Lake Granbury and Lake Whitney. "It's our expectation to be able to go through our priority list of stocking sites if we can obtain the fry," offered Saul. "The lakes that were affected by the golden algae are the highest priority for any fish we can collect. But some of our restoration efforts may be compromised due to the loss."
Although the loss of hatchery stocks are rare, there is that risk, said Saul, and to ensure some production success, TPW relies on more than one facility in the state hatchery system. Unfortunately, the other hatchery used for striped bass production, Possum Kingdom, is not on line because of a $5 million renovation project for much-needed infrastructure repairs to the 50-year-old facility.
The loss at Dundee came despite intensive efforts by hatchery staff to monitor water conditions. "We knew we had golden algae in Lake Diversion and had crews out there surveying to make sure the bloom was complete," Saul said. "We had excellent success with our spawns, stocked the grow-out ponds and checked often to monitor growth of the fry. Then the fry just disappeared. Even though we couldn't find an active algal bloom, obviously the toxins were still in the water in high enough levels to have an affect on the fry."
Because the toxins were present in water used at Dundee, hatchery officials had taken precautions including treating the water with chemicals to thwart the algae and transferring other brood stock, including largemouth and smallmouth bass, to the A.E. Wood State Fish Hatchery in San Marcos.
"The problem we faced was trying to determine how much chemical treatment we could use without impacting water quality. During the first 12 days of life, striped bass are sensitive to changes in pH levels, a high pH can be fatal," said Joe Warren, Hatchery program director with TPW. "We went with a chemical treatment that was the least intrusive on our water quality and tested it on sample fish first. What we didn't have was a method to actually test and measure the level of toxins."
Saul said the department is bringing together a team of biologists and scientists to find answers. "We need to know what we can do now if the algae is still persistent and what needs to be done in the future to avoid another catastrophe," he said.
Hatchery officials will use Dundee's disinfected recirculating water system if more female brood stripers are collected, said Warren. "We plan to sterilize the water in the incubation system and won't be bringing in any fresh water."
The overall health of the state's striper fishery will not be seriously jeopardized if biologists are unable to pull off a spawn this year, Saul assured. "There have been times in the past when stockings have not been successful and as a result a year class is lost in the population," he explained. "We may be looking at that scenario in some of our striper lakes this year.
"Fisheries officials in Oklahoma and Louisiana have been notified of the loss of Texas fish and are working to help us find additional striped bass brood fish," said Saul. Our neighbors are working with us to try and help us through this crisis."
Would you like to know more?
The Biology of Golden Alga summarizes what we know about the alga and its toxins.
Where does golden alga fit compared to other single-celled organisms?
The Golden Alga Family Tree gives examples of and information about golden alga and other protists.
What does golden alga look like?
TPWD Golden Alga Images has photos of fish kills, golden algal cells, and short videos of live golden alga. These images may be used for noncommercial/educational purposes as long as TPWD is given credit and other site policies are followed.
Golden Alga Information Card: TPWD has collaborated with TCEQ and other entities to produce a golden alga information card(pdf document). The purpose of this card is to educate the public on golden alga blooms and answer some common questions. Hard copies of this card are available for free by contacting 512 389-8750.