Hydroacoustic surveys conducted by the North Dakota Game and Fish Department and South Dakota Game, Fish and Parks last July showed exceptional smelt populations in Lakes Sakakawea and Oahe. However, record releases from Garrison and Oahe dams resulted in substantial losses of smelt from the reservoirs during the later stages of summer.
Dave Fryda, Missouri River System supervisor for the North Dakota Game and Fish Department, said entrainment rates with the record flows were very high and reduced the smelt population in both reservoirs.
“Smelt numbers in July in Sakakawea were equivalent to the good years of the late 1990s and early 2000s, and Oahe had possibly its best smelt reproduction in at least a decade,” Fryda said. “As coldwater habitat declined and smelt concentrated lower in the reservoirs during August and September, losses accelerated. It appeared most young-of-the-year smelt in Lake Oahe were lost, as well as a significant portion of the adult population.”
Smelt losses for Lake Sakakawea were also substantial, Fryda said, but likely not as severe.
“Now we are coming into spring knowing we lost quite a few smelt in both reservoirs,” Fryda added. “Given high to record number of fish predators, smelt spawning conditions this spring will be critical. We have good water levels in both reservoirs, habitat conditions should be good and we still have plenty of adult smelt in both systems. If we can pull off a good smelt spawn, especially in Oahe, we could recover very quickly.”
Despite losses of smelt, Fryda said there is some good news in the short-term for anglers as both reservoirs have healthy walleye populations and northern pike abundance has never been higher.
“Fishing should be good this summer in Oahe and the Garrison Reach of the Missouri River because of the suppressed forage issues and the high numbers of walleye and pike,” he added. “In addition, both reservoirs have a lot of young walleyes out there, and they likely will be on the bite.”