North Dakota fisheries crews this year collected a typical amount of eggs during their annual salmon spawning operation on the Missouri River System, but a wet summer of high water meant they had to use an atypical method to do it.
Crews who recently completed the operation collected more than 1.6 million eggs -- easily enough to stock the 400,000 smolts planned for Lake Sakakawea in 2020, according to Dave Fryda, Missouri River System supervisor for the North Dakota Game and Fish Department.
Unlike past years, the majority of eggs this year were collected from the Garrison Dam Tailrace and the Garrison Dam National Fish Hatchery salmon stream instead of from the back shoreline of bays in Lake Sakakawea, Fryda said. The average size of female salmon was 6 ½ pounds, similar to the last few years.
“The high releases through Garrison Dam this summer, which continued through the fall, resulted in extensive entrainment of salmon from Lake Sakakawea,” Fryda said, referring to fish being swept through the dam. “Salmon were scarce in Lake Sakakawea during the spawning season but abundant below the dam. In fact, 94% of all eggs collected in 2019 were from below the dam.”
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That's a dramatic change from recent years. The next-highest percentage of salmon eggs collected below the dam this decade is 43% in 2011, and in six of the preceding nine years the percentage was below 20%, Game and Fish data show.
Annual tagging of young salmon prior to stocking allows positive confirmation that the abundant salmon found below Garrison Dam were from fish stocked in Lake Sakakawea, Fryda said.
Chinook salmon begin their spawning run in October. Since salmon are not native to North Dakota and cannot naturally reproduce in Lake Sakakawea, personnel with Game and Fish and the fish hatchery collect eggs and transport them to the hatchery. Once the eggs hatch, young salmon spend several months there before being stocked in Sakakawea.
This year's take of 1.6 million eggs is on par with the 10-year average, according to Game and Fish data.
Extra eggs this year were shipped to South Dakota on Tuesday for stocking in Lake Oahe, according to North Dakota Fisheries Chief Greg Power. In some previous years, extra eggs also have gone to Montana for stocking in Fort Peck Reservoir.
"The three states work together and share if/when needed," Power said. "Fortunately, it's been more than 10 years since North Dakota needed other eggs, and most years we've produced the excess."