VIDEO: Utah is dropping thousands of fish from planes
(CNN) -- A few times a year over Utah's mountainous lakes, it rains fish.
Fish are not meant to fly, of course, but when the Utah Division of Wildlife Resources needs to restock the state's high-elevation lakes and streams with tiny trout, it will often dump them from a low-flying plane into the water over 100 feet below. The process, according to the wildlife agency, is surprisingly painless and generally survivable for the little fish.
The wildlife division shared a video this month of the aerial stocking process (the method by which fish are strewn from the sky), slowed down in parts to show the fish frenziedly flopping in as they're released. The footage is then sped up again to prove just how quickly the plane gets the job done. At first glance, the trail of airborne fish more closely resembles steam or smoke than a deluge of trout.
It's an unusual sight, but aerial restocking happens several times a year and has been in practice since the 1950s, according to the division. Pilots can dump up to 35,000 trout into 40 to 60 lakes within a few hours -- a process that is speedier and more efficient than pumping fish through a pipe that empties into a lake, the common method for restocking lakes accessible by cars.
Many lakes and streams in the state reside in its mountains and aren't reachable by roads, so pilots hover around 150 feet above these lakes to deposit the fish semi-gently into their new homes. About 95% of the fish survive the drop, the wildlife division told CNN in 2018.
Though they're falling from a great height, the stocking process takes just a few hours, which means the fish spend less time waiting to drop. That means they won't feel as stressed, and more of them will survive the transfer, according to the division. (It's also less tedious for wildlife officials to drop them in this way than the old method of carrying them on horseback.)
Aerial stocking can take place a few times every year, usually starting in July. Rainbow, brook and tiger trout are plopped Into the mountain lakes. These fish are around just 2 to 3 inches in length, which the division says helps them "flutter down slowly" into the water.
The native fish begin their lives in hatcheries, CNN affiliate KSTU reported in 2014, oblivious that they will soon be airborne. They'll stay there until July, when the aerial stocking season starts. The rainbow, brook and tiger trout are sent out first -- later in the season, cutthroat trout join the mix.
It's good news for fishing enthusiasts and other native species when more native fish enter the water. The primary reason the division stocks fish is to make sure there's enough animals available for recreational fishing, the division said last year, and the fish it stocks are often sterile so they can't repopulate lakes on their own. Other species, like the cutthroat trout, are released to prey on other fish whose populations may grow too large, throwing their ecosystems out of whack. Some fish just need the extra boost to their ailing populations, the division reported.
As for the fish, they're acclimated to the water temperatures before their fall and studied after the drop to see how many survived. They serve a purpose for Utah residents and other native species that rely on them -- and they fulfill that purpose after a few seconds of falling from the sky.
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