Sea hare ID, Lembeh Strait, Indonesia

[echeng 0]

Over 2 days here in Lembeh, I saw about a dozen tight groups of hundreds or thousands of these little slugs in the sand. They advanced in a line and looked like they were feeding. During one night dive, a group of them climbed on top of each other, forming a thin, tall tower that swayed in the current (Mean has video of this).

 

The big ones were about 1.5 inches long, but there were also lots of little ones in the mix.

 

We couldn't find them in our slug books, but they look like sea hares. Can anyone help ID?

[Leslie 0]

Stylocheilus striatus. There's a lot of posts about these aggregrations at the Sea Slug Forum although this is the first I can remember hearing of a tower!

http://seaslugforum.net/stylstri.htm

[echeng 0]

Thanks, Leslie! I'll try to get Mean to post the tower video. It's quite strange!

[indigo 0]

Thanks, Leslie! I'll try to get Mean to post the tower video. It's quite strange!

 

We have the same aggregation in St. Vincent... I took this photo on Friday. I was excited to spot one, but then found hundreds! They weren't performing as in Erics picture, but I was very surprised to see so many in one place.

 

Sea Hare

Edited March 9, 2010 by indigo

[mean 0]

Thanks, Leslie! I'll try to get Mean to post the tower video. It's quite strange!

 

I'm gonna stuck with this super slow internet until end of March. Sorry guys, you have to wait for a while.

[MikeVeitch 0]

Eric, which site and what time?

[echeng 0]

Mike:

 

Retak Larry at 9:26pm

TK3 at 11:19am (a bit deeper)

[ellenm 0]

They were swarming in Bonaire last week, as well!

http://www.pbase.com/imagine/seahares

[mean 0]

Finally, I have internet connection. Here it is the tower of Stylocheilus striatus.

 

http://www.vimeo.com/10281855

[Leslie 0]

That's really fascinating. (Of course I especially liked the swarming polychaetes that were zooming around ) Some years ago I saw 40 or more Aplysia californica forming a circle around the base of a boulder. That turned out to be a mating chain so I wonder if the tower could be a a different form of mating aggregation. I sent off a message to Bill Rudman at the Sea Slug Forum with the urls for this thread & your video Mean. He's bound to find it quite interesting.

 

For some great photos & more information on Aplysia mating chains see this thread on the Sea Slug Forum http://seaslugforum.net/showall/seahmat

[sgietler 1]

Sea hare aggregations (Aplysia sp.) like that are seen here occasionally in So-cal. But ours are drab-colored, those are beautiful! Great find.