RIVERDALE - Fish that thrive best in cold water, trout and salmon, can be found in abundance at the Garrison Dam National Fish Hatchery. The hatchery annually hatches and grows cold-water species during the winter months.
This winter the hatchery is caring for rainbow and brown trout and chinook salmon. The rainbows are known as "shastas," a proven strain of trout that grows quickly and does well both in a hatchery environment and in the wild. The Garrison Dam Hatchery shasta rainbows arrived in early January from the Ennis National Fish Hatchery in Montana.
"We have about 100,000 now. In about 15 months, we'll stock them out at about 10 inches in size," said Sean Henderson, Garrison Dam National Fish Hatchery. "They just started on feed recently."
Henderson has been at the Garrison hatchery for about two years, but raising trout is familiar work for him. He was previously stationed at the Ennis hatchery.
"Rarely did we have any trouble with Ennis brook stock and I haven't had any disease issues with the shasta strain here," said Henderson. "They are traditionally a good strain to culture. They do well. They grow fast. They take to feed well. They are just a good, solid, dependable culture strain of rainbow trout."
Other, older shastas in raceways at the hatchery's salmon building will be stocked into various North Dakota lakes later this year.
Young chinook salmon hatched at the Garrison Dam National Fish Hatchery last fall have continued to grow throughout the winter. The salmon are expected to reach 6 inches in length by the time they are stocked this coming summer.
Sean Henderson, Garrison Dam National Fish Hatchery, adds feed to a trough above a tank containing chinook salmon. The growth rate of the salmon has been slightly over 1 inch per month.
Brown trout are at the hatchery, but in lesser numbers than the rainbows. Newly hatched brown trout are estimated to number about 20,000. Those trout were recently moved to concrete raceways in the main hatchery building.
"They're on feed now, happy and healthy," said Henderson. "They are about 1.4 inches. Eventually we'll move them into the 8x80 raceways in the salmon building."
The hatchery received the brown trout in January from Ennis. A number of the young fish succumbed to a bacterial gill disease, something fairly common for the species.
"They get it religiously every year to the point where we order medicated feed to treat it when it arises," said Henderson. "It usually occurs about the same time they start feeding."
The growth rate for brown trout less is slower than the shastas, meaning they'll be held in the hatchery for a longer amount of time until they are released into the wild. Like the shastas, a number of older brown trout are occupying raceway space in the salmon building. They are scheduled to be stocked into the Garrison Dam Tailrace this summer.
Another fish of interest to North Dakota anglers, particularly those who fish Lake Sakakawea and the Missouri River, is chinook salmon. Thousands of the spotted fish move in unison in large raceways at the hatchery. They were hatched from eggs gathered from Sakakawea and the Missouri last October.
"They went on feed well. Their survival rate has been good. Their growth rate is good. They are growing fast, about 1.1 inches a month now," said Henderson. "They'll be about 6 inches when we stock them out."
Fifty-six degree water is cited as a major factor for the excellent growth rate of the salmon. The hatchery receives its water from Lake Sakakawea, and then heats it up for the salmon. The ambient temperature of the water coming from the lake is a mere 32.5 degrees.
"We've got a very short growing season. We've got the water heated to hasten growth," explained Henderson. "It is my second year with the chinooks and I haven't had any issues with them. They behave themselves."
Stockings of chinook salmon into Lake Sakakawea have averaged slightly more than 220,000 a year for the past four years, which is the amount of salmon currently being raised at the hatchery.