Sponges at cove 2

Fish & Invertebrate sightings and descriptions, hosted by resident NWDC ID expert Janna Nichols (nwscubamom).
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luv2dive
Getting To Know Folks
Posts: 6
Joined: Mon May 25, 2009 10:33 am

Sponges at cove 2

Post by luv2dive »

I found these sponges at Cove 2 in a jack straw by the honey bear.
Any idea what these are??
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Tidepool Geek
Aquaphile
Posts: 123
Joined: Sat Aug 20, 2011 10:36 pm

Re: Sponges at cove 2

Post by Tidepool Geek »

Greetings,

With a few exceptions, sponges are all but impossible to identify in the field and working from a photo is even less likely to be accurate.

That said, I'm not sure that this actually is a sponge. Sponges are characterized by (among other things) a huge number of water intake holes called 'ostia' (which may be too small to see without magnification) and a smaller number of water outlet holes called 'oscula' that should be large enough to see unaided - Maybe it's just old eyes but I couldn't see any obvious oscula in the photos.

What it looks like to me is a compound tunicate - possibly the invasive species Didemnum vexillum. More info on this species (including how to report sightings) can be found here: http://wdfw.wa.gov/ais/didemnum_vexillum/

Tunicates are characterized by having two siphons per animal although on a compound tunicate these may require magnification to see.

If you're willing to remove a glove, one way of telling a sponge from a tunicate is touch - a sponge will feel velvety to gritty while a tunicate will feel smooth & slippery.

Invasively yours,
Alex
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