Giant Dendronotus Video

[dwashbur]

We tried to go to Point Lobos yesterday, but the parking lot was full and they were turning divers away. So we went to the rocks at the Breakwater instead. We were glad we did. The scenario that was taking place just as my daughter got down to it and shifted her Canon A630 into video mode:

This Dendronotus iris, variously known as the giant dendronotid, giant nudibranch, rainbow dendronotus and a few other names, was in the process of laying an egg ribbon when a sunflower star came along, looked at the scene and said "lunch." Sunflowers move amazingly quickly, and he was on the egg mass before the nudibranch realized it. The nudibranch did realize, however, that if it stayed around, it too might become lunch, because sunflower stars basically will eat anything that doesn't eat them first. Still attached to the egg ribbon, the dendro took off swimming, as they are known to do. My daughter got there just as it was taking off, and the rest is self-explanatory. Enjoy!

swimming_dendro.flv

 

[rhlee]

nice catch

 

[pidgiepoo]

thanks for sharing--I've never seen one.

 

[dwashbur]

thanks for sharing--I've never seen one.

A couple of good places to find them: go along the rocks at the Breakwater to about 30 feet or so, and watch out on the sand for the fields of tube-dwelling anemones. That's where they hang out, because that's their favorite food. Basically, they crawl up to the tube, rear up and lean their head with the radula over the tube, and touch the inner tentacles. The anemone instantly sucks in, thinking "food!" But that's exactly what the nudibranch wants, because as soon as he gets drawn in, he starts eating the tentacles. Now the anemone is thinking "Oh, crap - I AM food!" But it's too late.

When you find the anemone fields, check around for egg masses like the one in the video. Chances are the nudibranchs aren't too far away. They vary in color from pale yellow-brown to deep purple and all manner of in-between, and you have to be looking closely to distinguish them from seaweed flotsam on the bottom, especially when there's a fair bit of surge.

Here's a video of another one we saw yesterday; this guy is doing his thing on one of the anemones.

MVI_1405.flv

Another place we've found several is out along the pipeline to the Metridium field. About halfway out on the ocean side of the pipe there's another really big field of tube-dwelling anemones. About all you can do is head for those fields and hope the nudis are out. Sometimes they're out in force, sometimes a couple are wandering around, and sometimes they all seem to be holed up sleeping somewhere else. But if you keep checking back at those anemone fields you'll find some sooner or later. And hey, if you don't find one today, it's a good excuse to dive again tomorrow!!

 

[Hepcat62]

We actually saw 2-3 of these things in the sandy patch to the left of the breakwater (among the tube anemones) on the 4th of July. The vis was absolutely incredible that day. Here's a video of one of them...

Beware - it may take a long time to start playing since that's basically the raw dump off of my camera. One of these days I'll get to converting it to something more useful.

 

[micboucher]

Wow, great videos! I've seen them quite a few times but never in action like that.

 

[TSandM]

What a great moment to see, and to capture!

Nudibranchs swimming always look like tormented souls to me.

Bob (NWGratefulDiver) has a beautiful photo sequence of one of these guys attacking a tube-dwelling anemone up off Vancouver Island. They're very cool animals.

 

[ryssyr]

I didnt know they could swim. Although it makes sense... I guess I never thought of how they get around besides crawling.

 

[dwashbur]

I guess these guys are known for swimming like that, especially when threatened. I don't know of any other nudibranchs that make a habit of it, although I have seen a swimming Dirona albolineata a couple of times. Whether they were doing it deliberately like the Dendronotus iris does, or whether they got knocked off their perch and just made the best of it, I don't know. Here's a shot of one in flight from Les Davis Pier in Tacoma, Washington. I call it "Wheeeeeee!":

 

[pidgiepoo]

I love his thread..I have never seen anything like these where I dive. I noticed most of you are located on the west coast (Washington, Calif etc). Do you find these mostly in the Pacific? I dive Cozumel alot and either I'm missing them..or they aren't there. Maybe someone who lives/dives Coz knows on what reef I might find one? Help Christi !! LOL