Freshwater jellyfish

[aanderud]

Was out with my son today fishing at a small lake in Chaska (Fireman's Pond) and we saw hundreds of these jellyfish swimming around - various sizes between a quarter and a silver dollar:

[PurpleFloyd]

Pretty cool thing. Hopefully you cleaned your boat real good so they don't get transferred to any other lakes. Are they an AIS?

[aanderud]

We were just fishing off of a public park fishing pier, but I was wondering if they're invasive/non-native and if so, why I hadn't seen them on any lists.

Googling around brings up quite a few hits related to them. They apparently are called Craspedacusta sowerbii

They appeared in a pond in massachusetts a couple years ago:

http://www.wickedlocal.com/concord/news/x90333751/Swimmer-finds-jellyfish-in-Walden-Pond-in-Concord

Quote:

The medusa, or grown jellyfish, does not live through the winter, so if the polyp population survives, the jellyfish may be seen again in Walden next year — or maybe not, says Peard, who does not believe the sudden appearance of jellyfish says anything about water quality at Walden Pond.

“I think it can happen anywhere depending on the availability of food and temperature of the water,” he said. “I’ve collected them everywhere from crystal clear ponds to farm ponds so polluted with manure that you wouldn’t want to swim in them.”

As it turns out, Acton had nothing to fear while swimming through the bloom of medusae. Although the jellyfish do have tentacles covered with stinging cells, they are not considered harmful to humans — their cells are so small they are unlikely to puncture human skin.

“Most people don’t feel anything,” Peard said. “I’ve been to farm ponds with kids swimming in them where the jellyfish are so thick the kids are coming up with them in their hair. We’ve handled them for 25 years and haven’t felt anything. So I think it is personal sensitivity.”

This one dude apparently likes them so much he has a HSOforum dedicated to them:

http://freshwaterjellyfish.org/

[c0untryf1sh3r]

I was talking to a coworker and apparently they had a piece on the news the other day about these things except they were farther up north, cant remember exactly where. I didnt believe her, thinking to myself "How can there be jellyfish in MN?" but now I see that its true.

http://minnesota.cbslocal.com/video?autoStart=true&topVideoCatNo=default&clipId=7659435

[CAMAN]

After the last thread was posted I did a quick research on them and couldn't find anything that stated they were considered AIS. I did see they were naturally occurring in many lakes, just certain weather patterns make them bloom more than others.

[Tom7227]

There was an article in the Duluth News Tribune on 8-18-12 about it. Normal but rare. I can't download the article because I don't have a subscription to the paper.

[weld1]

Not to change the subject but anyone fishing mille lacs ever catch a "worm" that looks like that black braided fishing line and there maybe 8 to 12" long? kinda creepy if you put them in a bowl of water they slowly move around!

[aanderud]

Not to change the subject but anyone fishing mille lacs ever catch a "worm" that looks like that black braided fishing line and there maybe 8 to 12" long? kinda creepy if you put them in a bowl of water they slowly move around!

I've seen one of those on the st croix.

[Knoc]

Thats pretty cool. Be cool in a aquarium.

[Sonicrunch]

hmmm.

Well, you learn something new every day.

[delcecchi]

I think they are called Nematodes and used to be called something about horse hair.

http://en.wikipedia.org/wiki/Nematomorpha

http://www.extension.umn.edu/yardandgarden/ygbriefs/e614horsehair.html

I originally saw one of these at the Science Museum of Minnesota behind the Capitol, in the mid 50's

[weld1]

Thats the one! caught a few of them over by hawkbill in the shallows, thought i caught someones old line!

[Scott M]

Nice Find aanderud!