Jellyfish Found in an Idaho Freshwater Pond Stuns Local Dad

Quick Take

• Freshwater jellyfish have been quietly living in Idaho for three decades, and the fact that nobody noticed says a lot about how unusual this creature actually is. 30 years unnoticed →
• Unlike the jellyfish you'd dodge at the beach, this species has a surprising relationship with human swimmers, one that defies what most people would assume. Why swimmers are safe →
• Scientists can't predict when these jellyfish will suddenly appear or even explain why they do, and a University of Idaho professor's explanation reveals just how bizarre their life cycle is. The unpredictable life cycle →
• These jellyfish are already in 45 states, and researchers have a pressing reason to care about them even though they pose no danger to you. Why researchers are concerned →

At certain times of the year, beachgoers need to be cautious of where they swim or walk, as jellyfish may be present. This caution is not practiced in lakes or ponds, as jellyfish are primarily saltwater creatures. However, a jellyfish was recently spotted in a most unusual place: none other than a freshwater pond in Idaho.

Jellyfish Discovered in Idaho Pond

Jellyfish are common in the ocean. As temperatures rise, the potential of jellyfish blooms is very real. However, people living in landlocked states do not give jellyfish a second thought, believing fresh bodies of water are safe from the stinging creatures. Imagine one father’s surprise when he found jellyfish in a pond located in a popular park.

Recently, Marc Brandes and his daughters were enjoying a day of swimming at Freedom Park in Star, Idaho. Swimming in the east pond, Brandes saw what appeared to be a foreign body in the water.

“I thought it was a feather, or some gross mucusy thing floating around there,” Brandes explained to the Idaho Statesman. “Then I realized it was moving.”

Brandes and one of his daughters collected the small jellyfish in a bucket. The peach blossom jellyfish was not alone, though. By the time Brandes and his three daughters were done searching, they had captured 15 or 16 jellyfish.

Brandes’ daughters called the encounter nothing short of “crazy.”

Freshwater Jellyfish Have Been in Idaho for 30 Years

While Brandes may never have seen a freshwater jellyfish before, they have established small populations in the state. In fact, the peach blossom jellyfish has been observed in Idaho for the past 30 years.

Idaho is not alone in having freshwater jellyfish. Across the country, 45 states have noted the presence of these creatures. The biggest problem that researchers have is understanding where the peach blossom jellyfish come from.

Because the jellyfish are no larger than a penny, tend to be in small groups, and are translucent, they are difficult to spot. Because of this, studies on the species are limited.

Freshwater Jellyfish Do Not Pose Harm to People

Unlike saltwater jellyfish, which have tentacles that pierce the skin, freshwater jellyfish do not. Consequently, the small jellyfish do not pose any threat to people.

This is not to say that freshwater jellyfish lack nematocysts. They still have the stinging cells in their tentacles. But they are smaller, since these jellyfish target zooplankton.

The bigger threat posed by creatures like the peach blossom jellyfish is that they are an invasive species. Originally from China, the jellyfish could become a competitor to other species that target zooplankton. The jellyfish could also alter freshwater aquatic habitats.

The limited research shows that the peach blossom jellyfish has not reached population numbers high enough to pose a threat to native wildlife. Whether this could change is still being investigated.

Why Are the Jellyfish Showing Up Now?

Since jellyfish are not new to Idaho, it stands to reason that they are found in numerous ponds and lakes throughout the state. But why have these jellyfish never before been reported in Freedom Park?

The peach blossom jellyfish spends the majority of its life as a polyp. It can live for years in this state and suddenly emerge as an adult jellyfish. Unlike saltwater jellyfish, which are known to create blooms when temperatures rise, it is not known what drives the peach blossom variety to mature.

This jellyfish species exists as adults for a much shorter time than they do as polyps. The adult stage is less than two weeks. This, according to Frank Wilhelm, a professor of limnology at the University of Idaho, is what makes learning more about the species difficult.

“It’s really hard to study them because they show up suddenly, and they don’t show up every year,” Wilhelm explained to the Idaho Statesman. “It might be 10 years between their emergence as adults in their life cycle, and then they’re around for a week to 10 days.”

For now, how the peach blossom jellyfish got to the pond remains a mystery. But it’s an incredible story Brandes and his children can tell about aquatic life in Star, Idaho.