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