can live a long, long time
Montana Fish, Wildlife and Parks
We just got back from a 150-mile boat ride in the wind on the Missouri River and are now sitting indoors entering relocations of our marked fish and catching up on the Missouri River Adopt-A-Fish program.
Mrs. Delgado's fourth graders in Whitefish wrote and asked about the ages of their fish. They're both older than the kids in the class but much younger than old guys like Mark Henckel and me. Their blue sucker is probably about 15 years old and their paddlefish is around 20.
All of the fish species in the Adopt-A-Fish program could be around for many years to come. Blue suckers have been aged at over 20 years old, shovelnose over 25, and paddlefish and pallid sturgeon could reach 40 or possibly over 50 years old! Generally, a fish species that grows fast and reproduces every year will have a short life span. It requires a lot of energy to grow quickly and there is a lot of stress in going through the spawning process.
Our Adopt-A-Fish species grow very slowly, and with the exception of the blue sucker, spawn every 2-4 years. This allows enough time for their body to recuperate before they go through the stress of spawning again. Another factor that influences longevity is average water temperature. For example, the shovelnose in Montana can live almost twice as long as shovelnose in the state of Missouri. The shorter summer season results in a lower average water temperature, which allows the fish here in Montana to grow and mature much more slowly than a fish that lives further south.
There were a couple of noteworthy movements of our adopted fish this week. Flows in the Milk River have tapered off and most of the blue suckers that went up the river early on have decided to leave the Milk and wait for another spring pulse of warm turbid water. All except for Blue Sucker No. 2, which has not passed by the ground station and must still be up there -- somewhere. The blues are stacked just below the Milk, however, I think they are going to be disappointed about this years mountain run-off. Not much flows coming down.
Shovelnose No. 4 finally warmed up a bit and decided to move around a little for the first time this year. He was slow to move last year also, but he ended up making a long swim into the Yellowstone and back up the Missouri.
Another first time mover was pallid sturgeon No. 1, which was originally tagged a couple miles below Fort Peck Dam. It went up as far as it could go - right up to the powerhouses.
During our 150-mile trip on the river, we were also recording locations of eagle nests, blue heron rookeries, and turtles for one of our local wildlife biologists. It was a most pleasant day on the river despite the wind.