What's this?

[mislav]

I'm no marine biologist, so excuse me for asking a simple question: What is this?

 

[justleesa]

always helpful to know where you saw it and at what depth

 

[mislav]

Of course.

There were many laid out on a rocky seabed at 5 to 15 meters of depth. The location is northern Adriatic sea - more precisely: some bay with very low viz but teeming with giant tubeworms and huge sea stars. And these things...

 

[archman]

Compound tunicate maybe? The image is blurry but I *think* I see little teeny incurrent siphons ringing bigger excurrent ones.

I've never seen a tunicate colony sitting on the bottom like a big poop pile, however.


Another wild guess is a calcareous sponge.

 

[mislav]

Yes, it was next to impossible taking a good photo of it in that murky water and it being so white. :shakehead

If it helps - they were about 20-30 cm tall and had a mouth-like orifice on top. Here's perhaps a better photo:

 

[archman]

Did you touch any? Was the texture rubbery, or *crunchy*?

 

[mislav]

Nope, I haven't touched it, so no idea. At first I thought it were eggs of some sea creature, but as you said - it is more likely to be a sponge of some kind or a compound tunicate.

Thanks, Arch!

 

[LeslieH]

I think it's a solitary tunicate - do an image search for Phallusia mammillata. Here's one site http://www.mer-littoral.org/32/phallusia-mammillata.php

 

[Mako Mark]

that is a "squidgy gooey fishy thing",

very different from the "creepy crawly crunchy critter things"



Actually, my guess is a sponge, great colour.

 

[archman]

I think it's a solitary tunicate - do an image search for Phallusia mammillata. Here's one site http://www.mer-littoral.org/32/phallusia-mammillata.php

Yeah, that's almost certainly it. The colour is spot-on, and so's the substrate. Wow, how on earth did you track this down Leslie?

I have no idea what that website is saying, other than reading "Mediterranean".