Last week, the Division of Wildlife Resources in Utah air-dropped thousands of fish in over 200 lakes around the state. This is part of the department's annual efforts to restock lakes with fish that are native to these lakes and used for recreational fishing. This year, they shared a video of the drop on their YouTube channel.
However, this isn't the first time the department has done something like this. The airdrop has been in practice since the 1950s, according to a document shared by the state government.
Conventionally, the restocking exercise is done by carrying young fish holding tanks that are transported by road on trucks, but Utah has many high-altitude lakes that are hard to reach by motorable roads. The department often uses creative methods like sending biologists on a hike with smaller 'makeshift' holding tanks and using horses or all-terrain vehicles (ATVs) to travel through tricky terrains, but air-dropping the fish has been the easiest method so far.
The plane has multiple holding tanks allowing for different species to be released in a single trip, avoiding monocultures as well. Fish are weighed before the trip and a single drop can release up to 35,000 small fish or fingerlings. These 1-3-inch-long (2-7 cm) fish flutter down slowly with the water in the holding tank, ensuring their survival. The Department of Wildlife Services has also carried out surveys of fish survival after aerial stockings and has come to the conclusion that survival rates are pretty high.
While the department did not specify which species of fish they restocked, the Food and Agriculture Organization of the United Nations states that carp, rainbow trout, Nile tilapia, and pikeperch are the most commonly used species in restocking. Aquaculture installations provide the fish for restocking purposes, which can be expensive but provides larger outputs, useful for large-scale restocking efforts such as one completed by Utah.