More than 2,000 paddlefish released in Caddo Lake after flows adjustedBy Sara Carney
After decades of absence from Caddo Lake, the American paddlefish, an ancient North American fish, began making a comeback earlier this year.
In March 2014, the Texas Parks and Wildlife Department (TPWD) and the U.S. Fish and Wildlife Service released 47 young paddlefish from the Tishomingo National Fish Hatchery in Oklahoma into Big Cypress Creek, a tributary of Caddo Lake. After initial success, an additional 2,000 paddlefish were released in September.
This is not the first attempt to re-establish the paddlefish in Caddo Lake following its disappearance after construction of the Ferrell’s Bridge Dam on Big Cypress Creek. But, this reintroduction differs from previous attempts because water releases from the dam were adjusted prior to the paddlefish’s arrival. The dam, which created the Lake O’ the Pines Reservoir, was built for flood control and water supply in Jefferson and the surrounding cities.
To re-establish the paddlefish population, the Caddo Lake Institute and The Nature Conservancy coordinated with the U.S. Army Corps of Engineers and the Northeast Texas Municipal Water District, as part of the Cypress Basin Flows project, to adjust the flows into the lake to better support the species’ needs.
“We’ve prepared the way this time,” said Rick Lowerre, president of Caddo Lake Institute. “I think before they were just reintroduced without anybody thinking about what changes might be needed to encourage them to stay.”
The idea to reintroduce the paddlefish came from a 2005 report by Texas A&M University scientists, including Dr. Kirk Winemiller, an aquatic ecologist in Texas A&M‘s Department of Wildlife and Fisheries Sciences. Winemiller said the report demonstrated the importance of natural flows into Caddo Lake and described lake conditions before Ferrell’s Bridge Dam was built. The scientists suggested that, once re-established in the lake, paddlefish could serve as an indicator species, alerting managers and stakeholders to changes in the ecosystem.
The paddlefish’s sensitivity to flows and its threatened status make it an ideal indicator species, Winemiller said.
Animal species, both aquatic and terrestrial, are responsive to the magnitude and timing of river flows, the report said. Many fishes rely on flows to stimulate spawning and migration and to facilitate dispersal and survival in early life stages. During the spring, when flows would increase, rocky shoals in Big Cypress Creek were used by paddlefish and other fish species for spawning.
Animals aren’t the only ones affected. Riparian trees, such as the bald cypress, use high flow pulses to transport their seeds. Flows also create appropriate soil moisture conditions for germination and seedling survival.
“The whole project is really more than just the paddlefish,” said Tim Bister, the local fisheries biologist with TPWD. “The bigger picture is creating a more natural river flow throughout the year by having certain water releases from Lake O’ the Pines mimic that natural river flow.”
The flows project should be thought of more as rehabilitation rather than restoration, Winemiller said.
Experts agreed that the flows will likely never be fully restored to their original state, but they say that the flows can be managed so that the needs of both the environment and people are met.
“The Caddo Lake situation is a model for the rest of the state,” Winemiller said, referring to the collaboration between the participating entities on the flows project. “Hopefully, in the future, we will see more cooperative efforts like this in other parts of the state.”
To learn more about the paddlefish reintroduction, visit Caddo Lake Institute’s website or The Nature Conservancy’s website. Also, see the Texas Parks and Wildlife Magazine article on the paddlefish release.
Look out for more in-depth coverage of this story in the next txH2O.