Ijams Quarry canoe trip: it's like déjà vu all over again

Canoeists on Ijams Quarry Lake

Anyone for jelly babies? Well, actually they are not babies but full-grown adults.

I expected we'd see herons and turtles on our canoe trip on Ijams Quarry Lake this morning, but I didn't believe we'd find the rare freshwater jellyfish that appear occasionally. Afterall, we found them on last month's canoe trip and even that seemed late in the season to me. The medusas' appearances called "blooms" are sporadic and unpredictable from year to year. It usually happens during the hot weather of the late summer months, or a least that's what I believed.

Yet, even on a cool morning in mid-October we found them. 


Freshwater jellyfish (Craspedacusta sowerbyi) are not native to North America. They first appeared in the lake at Ijams in 1997.  Since then, I've always thought they were rare, yet on two canoe trips in a row, we have found them.

The small bell-shaped jellies—about the diameter of a U.S. penny in their hydromedusa stage—are virtually transparent and as wispy as the Smoky Mountains' smoke. 

They look like bubbles, bobbing up and down, undulating underwater; one of the most ephemeral lifeforms I've ever seen or written about. Here one minute and gone the next, and surprise, surprise, they were here again this morning. 
What did Yogi say, "It's like déjà vu all over again."


The next guided canoe trip of the quarry lake is scheduled for Saturday, November 12 at 10:30 a.m. To register for it call 577-4717, ext. 119. 


- Story and text by Stephen Lyn Bales.

Canoe Trip Group

Ijams canoeists find ephemeral treasures

Ijams September canoe group

The first Ijams guided canoe trip open to the public on Ijams Quarry Lake turned up an oddity, ghostly aquatic apparitions.

I expected we'd see herons and turtles, which we did, but I didn't believe we'd find the rare freshwater jellyfish that pop up occasionally. The medusa's appearance is sporadic and unpredictable from year to year.


Freshwater jellyfish (Craspedacusta sowerbyi) are not native to North America. They first appeared in a greenhouse aquarium in Washington D.C. in 1907. Since then, they've slowly spread across the country and are usually found in calm, freshwater reservoirs, impoundments, gravel pits and old quarries. Ninety years after they were collected in the nation's capital, the jellies first appeared—or were first documented—in Mead's Quarry Lake in 1997. (Retired TVA biologist Bob Terry, husband of Ijams educator Jean Terry, identified them from collected samples.)

Generally, the small jellies appear in their medusa stage during the heat of summer. This is why I didn't expect we'd find them in mid-September on a cool morning. Lynn Keffer, a canoeist in our group, was the first to see one undulating just below the water's surface, virtually transparent and as wispy as morning fog. About the size of a penny, the jellies are clear to slightly milky white. Walter Cromer, another paddler in our group, quickly became attuned at spotting them swimming around our canoes.

They look like water bubbles, bobbing up and down underwater; one of the most ephemeral lifeforms I've ever written about.

Jelly watchers

C. sowberbyi

The next guided canoe trip I'll be leading is scheduled for Saturday, October 15 at 10:30 a.m. To sign up call me at 577-4717, ext. 119.

- Story by Stephen Lyn Bales