The last thing local photographer Hank Blum expected on a hike to a high alpine lake outside Silverton was a low-flying plane that dropped some unknown substance.
But Blum, camera in hand, caught the flyby on video during his August hike to Eldorado Lake, which sits at about 12,500 feet in elevation.
“Super shocked,” Blum said of his initial reaction. “We thought it was search and rescue.”
As it turns out, the plane was one of Colorado Parks and Wildlife’s fleet that is tasked with stocking remote lakes in the high country with fish.
Steve Waters, a pilot for CPW for the past 15 years, said there are 460 lakes around the state that receive fish drops.
CPW’s fleet of four Cessna 185 planes alternates each year between stocking lakes in the northern and southern parts of the state. In two weeks’ time, usually in September, the most ideal time to stock, CPW pilots stock about 230 lakes.
“We can do nine lakes per load,” Waters said. “So with four airplanes working, it goes pretty fast.”
Missions typically start early in the morning, when temperatures are cooler and winds are calmer, making it safer for flights.
Pilots typically do a first flyover of the lake they intend to stock, looking for any obstacles and to judge wind direction, Waters said.
If conditions are right, pilots will swoop back around to make the drop. The ideal speed is about 90 mph, Waters said, and airplanes should be about 100 feet off the ground. It’s a tight window.
“(The fish) need to have enough time to fall to lose their forward momentum,” he said. “You want them to hit the water straight down.”
The number of fish in each drop varies, depending on the lake. But on average, Waters said a load will carry 700 to 800 fish. It adds about 400 pounds to the plane.
Stocking fish from an airplane at such high elevations can be extremely dangerous, Waters said, and if conditions aren’t right, missions will be called off. Winds can be unpredictable and powerful in the high country, which can take a plane off its course.
“It doesn’t take a whole lot to make it undoable and wait for a different day,” he said.
Joe Lewandowski, spokesman for CPW, said airplanes started to be used for wildlife management purposes around the 1940s to stock fish in remote places, as well as to track big game. It became more commonplace in the 1970s with the advancements of radio collaring.