Re: Hitchhiker ID Please: Juvenile Abalone -- Haliotis asinina 3/24/09
<Hello Matt>
I pulled it out of the tank to get some better pictures.
<Thank you so much. What a beautiful little creature!>
To answer your questions, it has a hard shell almost completely flat and a foot like a snail. It is almost completely round, but when I photographed it, I noticed it is a little "U" shaped, or maybe like a kidney bean shape but flat. The pattern is on the shell part. It does not appear to bother any livestock.
<Nope, these are herbivores, so no worries.>
It stays in a 1 inch radius of the small indention in the rock that it is living in.
<Supposedly, these are nocturnal, so yours may well venture about at night, but return to the same spot in the morning. I've seen this sort of 'homing' behavior with urchins. If you didn't know better you'd swear they never left that one spot!>
It almost appears to filter feed, but definitely not sure about that.
<They actually feed on various algae species. Apparently, they prefer Rhodophytes (red algae) such as Coelothrix, Hypnea, Laurencia and Amphiroa, but will also feed on Gracilaria/Gracillariopsis. You could try offering yours some of the commonly available dried (red) seaweed sheets. The easiest way to present it is to tear off a piece and attach it to a rock with a rubber band. Simply set it near the animal, either right before the lights go out, or afterwards if you have any herbivorous fishes that would tear the sheet apart.>
The tentacles resemble Aiptasia.
<Yep, what you're seeing is a perimeter of sensory tentacles.>
Hope this helps.
<Yes indeed! These new photos are exactly what I needed. If you look closely at the shell, you'll see a line of respiratory holes (apertures) along the top edge facing the camera. These are common to Abalone (Haliotis spp.). The really neat thing, though, is the presence of those little blue spots. That clinches the ID as a juvenile Haliotis asinina, aka the Ass's Ear Abalone (because of the adult shell's supposed resemblance to a donkey's ear). Personally, I think that's an awful name for such a little beauty but oh well. These are common shallow water inhabitants of reef edges, and size-wise top out somewhere between ~2 3/8' and 4 ¾' (6--12cm). For more information, please see the following links: http://www.animalpicturesarchive.com/view.php?tid=2&did=25332
This next link shows the progression of shell development:
http://www.biomedcentral.com/1471-2148/7/160/figure/F1?highres=y
http://www.gastropods.com/9/Shell_119.shtml
Take care and enjoy your Abalone! LynnZ >