Jason Fox has taken hundreds of dives in the lake over 10 years and had never seen jellyfish until recently. “We actually did a fun dive on August 26 and my friend was actually the first one to spot the first one,” he said. Just a week later, on Sunday, September 4, another diving instructor was out with a group of students and spotted about eight jellyfish in the lake. On September 11, Fox returned to the lake and counted 22 jellyfish on his first dive. “And on the second dive, there were probably 50 or more,” Fox said. “I basically stopped counting. So, yeah, we were kind of surprised to see them there. I’ve been diving in that lake for a long time, and our instructor at the shop, he’s been there for at least 20 years.” Fox said the jellyfish were about the size of a dime or dime. “They won’t sting people because their tentacles are so small they won’t sting, but for maybe smaller fish, they might sting the fish,” he said. Diver Jason Fox found some small jellyfish introduced into Ramsey Lake in Sudbury, Ont.
Harmless to humans
Charles Ramcharan, emeritus professor of biology at Laurentian University, said the species of freshwater jellyfish is called craspedacusta sowerbii and is from the Yangtze Basin in China. “They came to North America a long time ago and also to Europe, and they just spread everywhere,” Ramcharan said. He said people have spread them in different ponds from ballast water, mud from people’s boots or even boat hulls. Although the species is not native to North America, Ramcharan said it is harmless to humans and the local ecosystem. “They have stinging cells, but they’re not strong enough to hurt anybody, so they’re really quite benign,” he said. Jellyfish have two life stages. When they float visibly in the water, this is called a manubrium. “So this is the stage of life that reproduces sexually,” Ramcharan said. “The other life stage is really weird. They reproduce vegetatively. So this is a life stage called a whorl.” Charles Ramcharan, professor emeritus of biology at Laurentian University, says the last freshwater jellyfish bloom in the Sudbury area was in 2003. (Markus Schwabe/CBC) Ramcharan said the jellyfish have been in the Sudbury area for decades, but they bloom and are visible to most people only on rare occasions. “The last time he was here was in 2003 when I moved to Sudbury,” he said. He said no one understands what makes them bloom. And they only exist for a few weeks. “I would tell people to get out there, swim,” Ramcharan said. “I know it’s cold, but just go swimming and go see them. You know, people pay a fortune to go to the tropics to see jellyfish. And now they’ve come to you.”
