Sampling and tagging more than 10,000 paddlefish along the Missouri River south of the Garrison Dam

BISMARCK, N.D. – Paddlefish are North Dakota’s largest fish species. In this week’s segment of North Dakota Outdoors, Mike Anderson tags along with fisheries crews as they sample paddlefish in the Missouri River.

North Dakota has two paddlefish populations, and both exist in the Missouri River System.

“One exists above Garrison Dam in the Missouri River System through Lake Sakakawea and up into the Yellowstone and Missouri rivers in the Williston area. And we’ve only got one other population here, and that’s our Garrison Reach population, this population between Garrison and Oahe dams. So, even though this population down here doesn’t support a recreational fishery, it still can provide really good insight on how to properly manage paddlefish in North Dakota,” said Paul Bailey, North Dakota Game and Fish fisheries supervisor.

Bailey and his crews have tagged, weighed, and measured around 10,000 paddlefish between Garrison Dam and the headwaters of Lake Oahe since 2006.

“And we’ve been able to estimate there’s usually around 9,500 to around 12,000 paddlefish in the Missouri River upstream of Bismarck at the time of sampling. And given that male paddlefish typically attempt to spawn once every two years, females typically every two or three years, the number of fish we see annually in the Missouri River upstream of Bismarck probably represents about half of the adult or sexually mature paddlefish in this population,” said Bailey.

Seasonal movements of paddlefish in the Garrison Reach are interesting, too.

“A lot of times later in the summer, there’s very few to no paddlefish in the Missouri River above Bismarck that these fish do have some annual migration patterns that they go through. That these fish, in all likelihood, are spending the bulk of their time in the headwaters of Lake Oahe, where zooplankton foraging conditions are much better for these fish,” said Bailey.

Paddlefish in the Garrison Reach do swim upstream in May when they get the urge to spawn.

“This reach of the Missouri River is likely way too modified due to the Garrison Dam for these fish to successfully naturally reproduce,” said Bailey.

If conditions don’t allow paddlefish to reproduce in the Garrison Reach of the Missouri River, how is this population sustained?

“We still see some mortality associated with entrainment of paddlefish through Garrison Dam, but in all likelihood, that’s one of the ways that we’re maintaining this fish population,” said Bailey.

Copyright 2023 KFYR. All rights reserved.