The “American” Paddlefish (Polyodon spathula) is now the only surviving paddlefish species on the planet. Historically there were six species, with the second to last remaining, the “Chinese” paddlefish (Psephurus glades,) declared extinct in 2020. The “American” paddlefish has inhabited Caddo Lake, as well as other rivers and bayous of the Mississippi River Basin for over 350 million years, making these beautiful fish 50 million years older than the dinosaurs and the oldest living species on our continent. Paddlefish are now rarely found in any rivers in Texas.
The Paddlefish’s diet consists primarily of zooplankton. The paddlefish is a filter feeder, capturing plankton on its gill strainers as it swims with its mouth open. Where they do thrive, Paddlefish can grow to seven feet, weigh 200 pounds and live for 30 years!
THE PADDLEFISH EXPERIMENT
Over the past half century, paddlefish populations have been on the decline. Attributable causes are over-fishing, pollution, and the encroachment of human development, including the construction of dams which block their seasonal upward migration to ancestral spawning grounds. Other detrimental effects include alterations of rivers which have changed the natural flow, and resulted in the loss of spawning habitat and nursery areas. Caddo Lake institute looks to restore this prehistoric fish to its natural habitat and help it thrive by bringing back the healthy flows to the lake and surrounding watershed that these fish require to survive, (see Flows Project ).
Caddo Lake Institute and their partners have experimentally released paddlefish fit with radio transmitting tags on the Texas side of Caddo Lake and facilitated two separate releases on the Louisiana side of the lake, (not fitted with transmitters). Paddlefish are long-lived, and sexually late maturing. Females do not begin spawning until they are seven to ten years old, (some even as late as sixteen to eighteen years old), so we do not yet know if they will reproduce in our restored system, but the survival rates lead us toward a full re-stocking of this once native fish on both sides of the lake!
This Paddlefish Experiment is one of many aspects of a larger effort to protect and enhance flows in the Caddo Lake watershed, and, thus, into Caddo Lake. That larger effort was begun in 2004 by Caddo Lake Institute with the technical support and leadership of the national Sustainable Rivers Project, a joint effort of the U.S. Army Corps of Engineers (USACE) and the Nature Conservancy. After 7 years of research, evaluations and testing, the 40+ scientists and 50+ stakeholders who participated developed recommendations for flow regimes for Big Cypress Bayou downstream of Lake O’ the Pines (LOP) and for Little and Black Cypress Bayous and for Caddo Lake. In 2011, the Corps of Engineers and the Northeast Texas Municipal Water District agreed to revise, for 5 years, some of its operations at Lake O’ the Pines and provide the flow regimes for Big Cypress to the extent water is available. In exchange, CLI agreed to perform several sets of experiments to evaluate the benefits of the new release patterns. The Paddlefish work is one of those experiments. The continued success of this project has led to CLI to assist with a second phase – the release of thousands of juvenile paddlefish into Caddo Lake to restore a viable population for the future.
With the change in water release patterns from LOP and the 2008 construction of a gravel bar for fish spawning by the U.S. Army Corps of Engineers, the experimental release of a limited number of paddlefish became possible. (See a video about the constructing of the gravel bar.) With funding from CLI and USACE, the US Fish & Wildlife Service (FWS) and the Texas Parks and Wildlife Department (TPWD) released four dozen, two to three-foot long paddlefish with radio transmitters on March 5, 2014 into the Caddo Lake watershed. With several telemetry towers and other monitoring efforts, employees of FWS and TPWD then tracked the movements of these paddlefish monthly. Data collected from that and from the capture and re-release of six of the paddlefish showed that, one year later, those fish were healthy and had shown significant growth. Monitoring of the fish and their habitat continued until this spring when the batteries powering the radio transmitters in the fish stopped working. News articles about the release can be found here. Local schools that had “adopted” and named a paddlefish, as well as the general public, were able to follow the fish. Based on the initial success in March of 2014, FWS and TPWD released 2000 young paddlefish into Caddo Lake in September 2014. These fish were smaller than those released initially, but they were tagged so they can be identified in the future. News articles about the release in September can be found here. The FWS released its report on this first phase of the Paddlefish Experiment in July 2015. It can be seen here
THE EDUCATION EFFORT
In early 2014, CLI and the Collins Academy of Jefferson, Texas launched an education program with area schools that includes teacher training and curriculum development by the Collins Academy. Individual and group projects resulting from the efforts were shown at the Paddlefish Festival in Jefferson in May of 2014, 2015 and 2016. Students and educators are utilizing this website to gain more information on the paddlefish, its habitat, the environmental flows work in the watershed and related work. They also used the website to track the movements of the tagged paddlefish that their school or other group adopted.
Phase 2 of the experiment is underway. Another release of paddlefish by FWS with the assistance of TPWD was made on May 18, 2016. Twenty seven of the fish were surgically-implanted with radio transmitters with batteries, so the fish can be tracked as they pass five receivers set up in the watershed. Several hundred other paddlefish, not tagged, were released at the same time. All of the fish released in 2016 were one-year old and about 12 inches long. This release and subsequent research helped to determine the long-term success of the experiment and resulted in further large-scale releases of paddlefish into the Caddo Lake watershed both on the Texas side and most recently, Louisiana.
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