RIVERDALE, (AP) - Chinook salmon have begun their run up the Missouri River and into a modified stream leading to the Garrison Dam National Fish Hatchery here.
Last year, the salmon struggled against the current to swim through thick stands of cattails, trees felled by beavers and sections of muddy bottom covered by only an inch or so of water. Now they are making their way up a channel that has been cleared. The new channel also has a gravel bottom and a few large boulders that the fish can get behind to get some relief from the strong current.
Hatchery manager Rob Holm said improvements were made to the channel over the summer. The salmon started arriving this week, he said.
"It was definitely not a spot where they could spawn and have survival of eggs," Holm said of the unmodified stream. "Now we're going to plant some grass and some willows and add some habitat down there. We'll make it look like a natural spawning area and let these fish actually do their thing."
The salmon were introduced to Lake Sakakawea 20 years ago.
The salmon swimming up the hatchery stream may provide enough eggs to maintain North Dakota's salmon program, Holm said.
"We can't bring in eggs from another source," Holm said. "Our chinook population is in jeopardy because the lakes have been so low. With this channel, we have an opportunity to go out and boost our collections."
Because of the low-water level in Lake Sakakawea, the Game and Fish Department has stopped using a salmon spawning ladder that normally operates each fall in Rodeo Bay. The lake salmon are smaller due to a dwindling forage base.
Biologists say other fish are filling in the gaps for a record low rainbow smelt population due to low water levels in Lake Sakakawea.
The department's fisheries supervisor in Riverdale, Jeff Hendrickson, said department surveys show anglers are catching more cisco, or lake herring. He said the smelt prey on young cisco.
"Prior to this year, cisco numbers have been kept in check by abundant smelt," he said. "In the short term, cisco and other fish, like goldeye, will fill part of the forage void left by a declining smelt population."
Hendrickson said biologists will continue to monitor the walleye population, which depends on forage in the lake. He said walleye fishing is still expected to be "respectable" next year.