Pallid Sturgeon Stocks – An Investment in the Future
BY COLBY WRASSE, COLUMBIA FWCO
captured from the lower Missouri River. Credit: Colby Wrasse
Recovery of the Federally Endangered Pallid Sturgeon is a multifaceted endeavor involving the collaboration of numerous federal and state agencies. Artificial propagation and stocking has been an important component of recovery efforts, with more than 135,000 Pallid Sturgeon stocked in the lower Missouri River since 1992. This accomplishment has required the combined efforts of two fish hatcheries (Neosho National Fish Hatchery and Blind Pony State Fish Hatchery), three fisheries offices (Columbia Fish and Wildlife Conservation )Office (FWCO), Missouri Department of Conservation, and Nebraska Games and Parks), United States Geological Survey (USGS) – Columbia Environmental Research Center, geneticist Dr. Heist of Southern Illinois University, and many others.
Columbia FWCO contributes to the cause largely through our broodstock collection efforts. Since 2007, we have fished the lower Missouri River with trotlines and gill nets, capturing large, “wild” Pallid Sturgeon to utilize in the propagation effort - but catching these fish can be challenging. A potential broodstock Pallid Sturgeon needs to be 1) an adult (usually greater than 30-inches in length), 2) a “wild” fish –not a previously stocked fish, and 3) reproductively ready (Pallid Sturgeon may spawn only once every 3-5 years). The combination of these three factors rule out many of the Pallid Sturgeon we capture. For example, during the 2013 season Columbia FWCO collected 65 Pallid Sturgeon; however, only 3 met the criteria necessary for potential use as broodstock fish.
Catching the fish is only the first step in the process. After a potential broodstock fish is captured, we then coordinate with the hatcheries for transportation of the fish – this could involve up to a five hour truck ride for the fish. We also send a genetic sample of the fish to Dr. Heist, who determines if the fish is 1) a pure Pallid Sturgeon (not a Pallid X Shovelnose Sturgeon hybrid), 2) a truly “wild” pallid sturgeon – not of hatchery origin, and 3) which management unit the fish genetically assigns to (a complicated story for another day). Biologists from USGS will also examine the Pallid Sturgeon with ultrasound and endoscope to determine the sex of the fish and its reproductive readiness. If a Pallid Sturgeon is genetically determined to be a good candidate for propagation and it is reproductively ready, then the hatchery biologists will work their magic and attempt to spawn the fish. The baby pallid sturgeon produced from artificial propagation typically spend about a year in the comfort of the hatchery before being tagged and stocked into various locations in the lower Missouri River.
Two of the Pallid Sturgeon we captured this year were reproductive males. With the ability to cryopreserve milt, the broodstock fish we collected this year could also be used in future years to increase the number and genetic diversity of Pallid Sturgeon in the lower Missouri River. Much has been learned about Pallid Sturgeon in the two decades since artificial propagation first began. Advancements in broodstock collection techniques, genetic analysis, spawning techniques and hatchery rearing have allowed us to continually improve on the propagation and stocking process, which remains an important component of recovery. We still have a long way to go to recover Pallid Sturgeon, but many dedicated professionals continue working together towards that common goal.