PIERRE, S.D.-After more than four years, a difficult search for eggs and a long rearing period, Atlantic salmon are coming to the Missouri River's Lake Oahe in central South Dakota..

During the next two years between 15,000 and 20,000 of the fish are slated to be stocked into the reservoir, said Will Sayler, who oversees the South Dakota Game, Fish and Parks Department's fish hatchery and stocking operations.

The state's first batch of eight to 12-inch Atlantic salmon will released this fall, with a second batch, barring unforeseen complications, next fall.

Once the fish are in Lake Oahe, it'll be a waiting game to see if any of the fish return to the spawning station and if anglers can catch them. That could take between two and three years, meaning the ultimate fate of South Dakota's Atlantic salmon program may not be decided until 2022.

In the meantime, the state's coldwater fish hatcheries will have some space freed up to accommodate more rainbow trout and chinook salmon, both species for which there is higher demand, Sayler said. The two-year classes of atlantic salmon currently being reared at both hatcheries take up a lot of space.

Atlantics are much harder to raise than their cousins from the Pacific Northwest. For one thing, they need more space, a fact that dashed GFP plans to retain Atlantic salmon broodstock at the hatcheries, Sayler said.

It'll be up to the Atlantic salmon that return to the spawning station to create a long-term source of eggs for future stocking efforts. Any potential for future stocking also will depend on whether or not anglers can catch them. One of the goals of the experiment is to see if they'd be easier for anglers to target, GFP officials have said.

Atlantic salmon are a bit more adaptable than chinook salmon and more likely to vary their diets when food is in short supply. After the 2011 flood, for example, when rainbow smelt numbers in Lake Oahe crashed, Atlantic salmon would have been more likely to switch to alternate food sources. That is unlike chinook salmon, which tend to fixate on a single food source and experience population crashes when that food source crashes, which is also what happened in 2011.

The ability to tolerate slightly warmer water temperatures might also mean Atlantic salmon would be easier for anglers to target. Another plus would be that Atlantic salmon can spawn more than once so they'd spend more time in the lake before dying off. Chinook salmon live for up to four years, spawn once and then die whether they return to the spawning station or not.

The Atlantic salmon stocked this fall be joined by the annual fall chinook salmon stocking, which will bring the number of chinooks stocked into the lake in 2018 up to about 320,000, Sayler said.