We've all heard stories of the beautiful but deadly jellyfish and all their oceanic manifestations. If you happened to catch the "Jellies" exhibit at the Shedd Aquarium, or if you've watched any tv shows on the subject, you know that they come in infinite varieties and are among the most fascinating organisms on the planet. But despite your fascination, you can certainly never dive with them; the risk is too great. Some have stinging tentacles so powerful they can kill a human being in six minutes. Entering the water with them around is reckless.
Or is it? Are there some circumstances under which you can enjoy the presence of jellies while you snorkel, swim and even scuba dive among them?
Today, I'm exploring the complex and often mysterious existence of several species known colloquially as "freshwater jellyfish," and the places you can see them and enjoy their beauty without worrying about their deadliness.
I should start by saying that, technically, "freshwater jellyfish" are not the same species as their oceangoing, fish-zapping cousins. The ones this blog refers to is the species C. Sowerbii, found in freshwater lakes on every continent but the Antarctic. The most distinct difference, other than the freshwater jelly's relative harmlessness, is a thin, membranous shelf-like wall that extends from the rim of the "bell" to the jelly's mouth. According to science, new membrane wall means new species. For the record, Science, I probably wouldn't have noticed.
These jellies are often no larger than a quarter and have a whole row of string-like tentacles around the rim of the bell that allow them to catch and consume their favorite meal: zooplankton, microscopic water-dwelling animals.While these jellies still use stinging cells to capture their microscopic munchies, they use them in such a small capacity that they are usually considered harmless to people, though some may be sensitive to it.
The peak season for these jellies is typically August and September in North America, when the water temperature in the inland lakes is warmest. They "bloom" in huge groups, and have been observed with growing frequency in the last few years, a phenomenon sometimes attributed to climate change. In Illinois alone, they've been spotted at two very popular dive sites, Mermet Springs and Pearl Lake. These jellies are only around for a few weeks after the first sighting, so diving and swimming with them is only available in that window. However, it is safe to be in the water with them, and they make fascinating and unusual photo subjects.
So, as it turns out, freshwater jellies are not just a rumor. Stay up to date on our local trips, and you may have a chance to dive with them this summer! If you want to know here else you can see them, This website has info on sightings across the United States: www.freshwaterjellyfish.org.
Or is it? Are there some circumstances under which you can enjoy the presence of jellies while you snorkel, swim and even scuba dive among them?
Today, I'm exploring the complex and often mysterious existence of several species known colloquially as "freshwater jellyfish," and the places you can see them and enjoy their beauty without worrying about their deadliness.
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| http://www.invertebrate-images.co.uk |
These jellies are often no larger than a quarter and have a whole row of string-like tentacles around the rim of the bell that allow them to catch and consume their favorite meal: zooplankton, microscopic water-dwelling animals.While these jellies still use stinging cells to capture their microscopic munchies, they use them in such a small capacity that they are usually considered harmless to people, though some may be sensitive to it.
The peak season for these jellies is typically August and September in North America, when the water temperature in the inland lakes is warmest. They "bloom" in huge groups, and have been observed with growing frequency in the last few years, a phenomenon sometimes attributed to climate change. In Illinois alone, they've been spotted at two very popular dive sites, Mermet Springs and Pearl Lake. These jellies are only around for a few weeks after the first sighting, so diving and swimming with them is only available in that window. However, it is safe to be in the water with them, and they make fascinating and unusual photo subjects.
So, as it turns out, freshwater jellies are not just a rumor. Stay up to date on our local trips, and you may have a chance to dive with them this summer! If you want to know here else you can see them, This website has info on sightings across the United States: www.freshwaterjellyfish.org.
