Healthy Fish Populations In The Missouri River System

The North Dakota Game and Fish Department recently completed its annual fish population sampling on the Missouri River System and found positive results in both Lake Sakakawea and Lake Oahe. The Missouri River from the Garrison Dam to Bismarck was not sampled due to high water.

Scott Gangl, fisheries management section leader, said when Lake Sakakawea began to refill in 2009, all fish populations started to rebound, beginning with the smelt forage base. “The drought of the early 2000s hurt fish populations because low water reduced spawning habitat and the available forage base,” Gangl said. “Now after a couple years of higher water we are seeing a turnaround.”

After years of drought, higher reservoir levels gave fish access to gravel and cobble spawning areas that were dry just a few years ago. There is also much more sheltered shallow-water habitat in the backs of bays that are important nursery areas for many fish species.

Recent netting operations in Lake Sakakawea found abundant walleyes, with many in the 18-22 inch range. Biologists also noted substantial numbers of yearling walleye in the nets, an indication of good reproductive and stocking success in 2010.

Northern pike, yellow perch and sauger were also plentiful in the survey nets.  Sauger numbers have been good in recent years, and the size structure is favorable for anglers. Meanwhile, northern pike and yellow perch reproduction has flourished since the return of water to the reservoirs. Although their size is still on the smaller side due to their younger age, Gangl said they are growing well.

Smallmouth bass are rebounding with the water levels as well, Gangl said, with good numbers of moderately-sized fish in the nets.

“All fish are in excellent condition and plump, a huge turnaround from a few years ago when drought conditions resulted in extremely skinny fish,” he said.

On Lake Oahe, the walleye population is still strong, with numbers similar to the past three years. Although larger walleye remain in Oahe, many fish in the nets were less than 14 inches in length. Gangl said the high numbers of small walleye is the result of strong reproduction since the lake refilled in 2009.

“Northern pike numbers on Lake Oahe are also through the roof, higher than we’ve ever documented,” Gangl added. “Like in Sakakawea, these fish are still growing in size and will produce some exceptional fishing opportunities in the coming years.”

Catfish were the most predominant fish in the Oahe nets.