Report: Jellyfish in Indiana

Sunday, October 19, 2008

According to a recent report by the Nature Conservancy of Indiana there are jellyfish in lakes, ponds and slow-moving rivers in Indiana. The site is rare but it does happen.

Jellyfish are usually found in salty seas yet the freshwater jelly can be found practically all over the world. Besides North Dakota, South Dakota, Montana and Wyoming every state has experienced freshwater jellyfish sightings.

Freshwater jellyfish (also known as peach blossom fish) - are considered nonindigenous aquatic species believed to be originally from China. They were first reported in the United States around the early 1900s, with introductions presumably coinciding with the transportation of stocked fish and aquatic plants. They've been spotted -- sporadically -- in shallow, calm bodies of water ever since.

"People find them once in a while and call us. It's not that unusual to see them. I know when you do see them it is usually a good indication that the water quality is high," said Jeff Malwitz, Assistant Manager of the Cikana State Fishery.

Researchers aren't quite sure why the occurrences of these creatures are so unpredictable. In some lakes and rivers, freshwater jellyfish may be present one year, but not the next. Then again, there are some waters that boast them almost every year.

Although the critter is touted as a jellyfish, some argue it is more related to the family Hydra than a "true" jellyfish. The main difference between the freshwater and "true" jellyfish is the presence of a velum, a thin, circular membrane around the cap that helps propel, or move, the jelly forward.

Yet freshwater jellies share many of the same characteristics of jellyfish. They are transparent, gelatinous, umbrella-shaped animals with a whorl of string-like tentacles around the edge of their body. Along the tentacles are microscopic barbs called nematocysts that help capture food and serves as a type of protection against predation.

It is this part that stings and causes intense pain to whatever it touches -- animal or man. Freshwater jellies are quite small -- an adult is the size of a quarter -- and there isn't any hard evidence that suggests that they can penetrate through the human skin the way larger, marine jellyfish can.

"There are present in lakes in Indiana although I've never seen one," said Malwitz.

Here are a few facts about freshwater jellyfish: they lack a head and skeleton. They contain no special organs for respiration or excretion. The body is made of 99% water.

Though small and practically see-through, they are easy to spot on sunny days as they tend to surface in large groups called blooms.

Their large, flat sex organs -- called gonads --are the only part of the freshwater jelly that is not translucent.

Jellyfish tend to stay near the bottom of shallow waters where they can conserve their energy for capturing food or escaping predators.

Freshwater jellyfish feed on super tiny aquatic animals called zooplankton.

Jellyfish are rich in protein and are eaten in many cultures around the world.

If you're interested in learning more about this jelly, visit Dr. Terry Peard of Indiana University in Pennsylvania's Web site on freshwater jellyfish at www.jellyfish.iup.edu.

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  • Our family was on vacation at Indian Springs this past week and saw tons of these jellyfish while swimming in their lake. Indian Springs is in Garrett Indiana. They encircled the platform we were jumping from and kept coming back after we got back on the platform. It was really neat! The kids were catching them in their hands and of course releasing them back. It was a great memory of our family vacation and one nobody will soon forget.

    -- Posted by mrs.shellenbarger on Sun, Jul 29, 2012, at 6:57 PM
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