Trouts on a plane: Utah drops fish into lakes from aircraft and circa 95% survive
Meanwhile, Minnesota city authorities evict dozens of monster goldfish from murky local lake
Authorities in the US state of Utah have released video of an extreme method they have devised to stock inaccessible lakes in its mountainous regions: a specially adapted aircraft that makes it rain fish.
The fish airdrops were devised as a method for stocking remote lakes as a challenge for anglers. The fish, young brook trout and tiger trout between one and three inches long, are not native to the lakes and do not breed, meaning their numbers have to be replenished on a yearly basis in order to maintain the volume.
To get the fish delivered accurately to their new homes, the aircraft – the one in the video below being a converted Cessna 185 Skywagon with a water tank installed in the rear baggage/cargo bay – fly into the target areas “just barely above the trees,” according to The New York Times.
The Utah Division of Wildlife Resources says the fish are acclimatised to the water temperatures and pH levels of each lake before they are loaded into the aircraft, and the water tanks on board are pumped with oxygen to keep the fish healthy.
Each flight can transport up to 35,000 two-inch fish, a quantity which can be dispensed into a suitable lake in a matter of seconds, according to Wade Wilson, a Wildlife Resources biologist who accompanies the pilots on the piscine delivery runs.
The authorities claim a very high success rate for the method, maintaining that the fishes' small size means they tend to flutter and fall more slowly, and that the survival rate for fish dropped in this way is around 95%.
Although video footage and public appreciation of fish-bombing missions is a new phenomenon, the flights themselves have been running in the early summer over the state since 1956, while more conventional forms of restocking have been utilised for even longer.
Prior to the use of aircraft, fish were carried to remote locations in metal milk cans carried by horses. Even today, fish are transported to small lakes and streams in adapted backpacks by dedicated wildlife workers on foot, on horses, on motorbikes and on four-wheelers in a practice known as extreme fish stocking.
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The Utah authorities claim that nobody has ever been hit by one of their fish dumps, which is just as well since a combined load of fish and water would weigh hundreds of kilos.
This does not mean that fish have not inexplicably fallen on people at other times, however. Rains of fish and other animals have occurred throughout history, with Pliny the Elder recording storms of fish and frogs in the first century AD, although it is unlikely the Utah Division of Wildlife Resources were responsible in that case.
A hail of fish was recorded as recently as 2004 in the town of Knighton in Wales, although to be fair, that probably wasn't the UDWR either.
Meanwhile, in Minnesota...
Another species of non-native fish has been causing problems elsewhere in the US, however. Authorities in Minnesota have appealed to residents not to release unwanted goldfish into the wild after a number of enormous cyprinids were captured in a lake in the state.
A survey of Keller Lake in the city of Burnsville earlier this month came up with ten examples, measuring up to a foot long (30cm). A subsequent further study this week yielded another 18, including some 18-inch (45.7cm) specimens estimated to weigh 4lb (1.8kg).
Goldfish are members of the carp family and contrary to their reputation as sickly, short-lived fairground prizes, they are in fact extremely hardy and adaptable. Although native to East Asia, escaped examples, deliberately-released pets and even ill specimens which have been flushed down toilets have thrived in the wild due to a shortage of predators, and have become invasive species all over the world.
Please don't release your pet goldfish into ponds and lakes! They grow bigger than you think and contribute to poor water quality by mucking up the bottom sediments and uprooting plants.— City of Burnsville (@BurnsvilleMN) July 9, 2021
Groups of these large goldfish were recently found in Keller Lake. pic.twitter.com/Zmya2Ql1E2
As the Burnsville authorities pointed out [above], they can grow to considerable size, compete with native species for resources, and have a detrimental effect on water quality due to their habit of digging up plants and sediment while looking for food.
While the portly examples found in Keller Lake are certainly at the larger end of the goldfish scales, larger specimens have been caught. The heaviest was a 5lb 4 oz, 13 inch orange-and-white whopper caught by 10-year-old Lois Chilvers in a lake in Kent, UK, while on a fishing trip with her dad. ®