Sampling and tagging over 10,000 paddlefish on the Missouri River south of Garrison Dam

Bismarck, North Dakota – The largest fish found in North Dakota are paddlefish. As fisheries teams sample paddlefish in the Missouri River, Mike Anderson joins them in this week’s episode of North Dakota Outdoors.

There are two populations of paddlefish in North Dakota, and both are found in the Missouri River System.

“One exists in the region of Williston above Garrison Dam in the Missouri River System through Lake Sakakawea and up into the Yellowstone and Missouri rivers. Additionally, there is just one additional population in this area, which is the Garrison Reach population, located between the Garrison and Oahe dams. Therefore, even if this population down here doesn’t sustain a recreational fishery, it can still offer extremely valuable insight into how to manage paddlefish in North Dakota, according to Paul Bailey, fisheries supervisor for North Dakota Game and Fish.

Since 2006, Bailey and his teams have tagged, measured, and weighted about 10,000 paddlefish between Garrison Dam and the Lake Oahe headwaters.

“And we’ve been able to estimate that at the time of sampling, there are typically between 9,500 and 12,000 paddlefish in the Missouri River upstream of Bismarck. 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, according to Bailey, given that male paddlefish typically attempt to spawn once every two years, while female paddlefish typically do so every two to three years.

It’s interesting to see the seasonal movements of paddlefish in the Garrison Reach.

The Missouri River above Bismarck frequently has few or no paddlefish later in the summer, despite the fact that these fish do follow seasonal migration patterns. The majority of these fish’s time is most likely spent in the headwaters of Lake Oahe, where the zooplankton foraging circumstances are far more favorable for them, according to Bailey.

The Garrison Reach paddlefish do swim upstream in May when they feel the need to breed.

According to Bailey, the Garrison Dam has significantly altered this stretch of the Missouri River, making it impossible for these fish to properly breed naturally.

How is this population maintained if the Garrison Reach of the Missouri River’s conditions prevents paddlefish from reproducing there?

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