Adult Reproductive Studies Benefit from Broodstock Collection Effort

Each spring biologists and volunteers from State and Federal agencies cooperate to collect adult pallid sturgeon from the Lower Missouri River for hatchery propagation.  Offices from the U.S. Fish and Wildlife Service, Missouri Department of Conservation, Nebraska Game and Parks Commission, and the South Dakota Game Fish and Parks send boats out to collect pallid sturgeon using trotlines and gillnets. The numbers of adults collected each year varies with the weather, river conditions, and luck.  Captured pallid sturgeon are transported by special tank trucks to one of the participating fish hatcheries, including the Missouri Department of Conservation’s Blind Pony Fish Hatchery, and the U.S. Fish and Wildlife Service’s  Gavins Point or Neosho National Fish Hatcheries. As the biologists on the river doing the collection are unable to discern reproductive fish from non-reproductive fish, all pallid sturgeon greater than 850 mm (33.5 inches) are taken to a fish hatchery to have their reproductive readiness assessed by USGS biologists using ultrasound and endoscopy. Fish that not reproductively ready are released back into the river as soon as possible, while those that are ready to spawn are held until conditions are right.

Pallid Sturgeon Undergoing Surgical Implantation

 Missouri Department of Conservation hatchery personnel look on as Aaron DeLonay, USGS sturgeon biologist, surgically implants a pallid sturgeon with a telemetry tag.

When fish are no longer of use to the hatcheries, they are often taken by USGS scientists and implanted with transmitters and data storage tags immediately before release.  This is an efficient way to increase the number of tracked sturgeon with known reproductive status and histories.  Greater numbers of sturgeon tracked provide a better opportunity to learn how well sturgeon are growing in the river and how often sturgeon reproduce.  Between April 30th and May 2nd, 21 pallid sturgeon captured during broodstock collection efforts were turned over to USGS biologists for surgical implantation of transmitters and data storage tags.  Four other fish already had transmitters when they were captured for in the broodstock effort.  These sturgeon were reimplanted with new tags.  All fish were transported back to the river and released where they were initially caught.   In the past year, 59 pallid sturgeon were tracked downstream of  Gavins Point Dam in the Missouri and Platte rivers. We hope that with increased numbers of fish being tracked, patterns of habitat use and reproductive behavior may become more apparent.

With contributions from Aaron DeLonay and Robert Jacobson

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