 lue suckers spend their lives swimming up and down the typically peaceful waters of the Colorado River, finding food on the river's bottom and traveling miles and miles for an occasional romantic rendezvous.
They have no way of knowing that Ed Oborny and the others working with the Lower Colorado River Authority are watching.
They watch from boats, from the shore and from planes. Every once in a while, they'll even put on a snorkel and watch from the water.
Why? The blue sucker (Cycleptus elongatus), listed as a threatened species of fish in Texas, is viewed as a sensitive species and a good indicator of the ecological condition of the lower Colorado River. So, generally speaking, healthy blue suckers mean a healthy river.
That's why LCRA hired Oborny's company, BIO-WEST, to study blue suckers and their habits.
LCRA-SAWS Water Project
LCRA and San Antonio Water System are cooperating on an ambitious project, called the LCRA-SAWS Water Project, that would provide more water in the future for both the lower Colorado River basin and the San Antonio region. The project would include the creation of one or more off-channel storage facilities in the lower basin to collect unused and excess river flows. The project could make available as much as 330,000 acre-feet of water a year through a combination of these unused and excess river flows, agricultural conservation and the conjunctive use of groundwater for agricultural use in the lower Colorado River basin (about 295 million gallons a day).
One important aspect of the vastly complex project is ensuring the protection of the region's sensitive aquatic life - like the blue suckers. Ensuring protection of aquatic life is part of LCRA's responsibility as a steward of the river.
"The flow regime of the Colorado River would change if the project is implemented," said Leah Manning, program manager of the LCRA-SAWS Project. "Because of that, we need to understand the effects of the project on the aquatic habitat."
That's where fisheries biologists from BIO-WEST and LCRA come in.
"This fish is a sensitive species," Oborny said. "It needs certain types of habitat and certain levels of water quality to survive and to be able to move up and down the Colorado River. The adult population tends to be relatively strong. A sensitive species like this one is a good indicator of the health of the river."
An important indicator
Bryan Cook, an LCRA aquatic biologist, said studies like the one focusing on the blue sucker are important not just because of what they tell us about a threatened species of fish, but because of what we learn about the Colorado River.
"There's a benefit outside of the LCRA-SAWS Water Project because this is such a unique fish," Cook said. "What we learn here will help us make sure we manage the river where it's not just a benefit to this threatened species, but for others as well."
About the fish
Blue suckers are frequently described as being torpedo-shaped. Adults can grow in excess of two feet long. They eat aquatic insect larvae, crustaceans, plants and algae - all of which are abundant in the lower Colorado River.
In the fall of 2004, BIO-WEST and LCRA biologists implanted radio transmitters in 30 adult blue suckers captured in the Colorado River downstream from Austin. The fish were then released back into the river. The transmissions can be detected by receivers that can be carried on a boat or even in an airplane.
Because each transmitter broadcasts on a unique frequency, Oborny and his team can tell which fish they are monitoring.
So far, there has been an excellent survival rate for the fish implanted with the transmitters and they continue to move up and down the lower Colorado River providing the study team data on migration, habitat preferences, and spawning locations.
If fact, during the spring, more than 70 percent of the movement was upstream with fish swimming more than 170 river miles to reach suitable spawning locations. Three tagged blue suckers moved between 55 and 115 river miles to meet just below Longhorn Dam in Austin to take part in spawning activities along with 40 to 50 untagged blue suckers.
Next phase of the study
Additional phases of the study will focus on juvenile and larval blue suckers. So far, that's been a tough job. It's possible the young fish stay hidden during the day to avoid becoming dinner for other larger fish. Or it's possible the researchers just haven't pinpointed their preferred habitat, Oborny said. Researchers will continue to adapt their techniques until they track down the younger fish.
After the blue suckers spawn next spring, the study will also focus on blue sucker eggs and larval fish. The entire project is expected to be completed in 2007. LCRA and SAWS received good news recently when President George W. Bush signed the U.S. Department of the Interior appropriations bill, which included $400,000 for the blue sucker study.
Jerry White is a writer for LCRA. |
