What is so small and moves in big groups?

Dashrynn · Post by **Dashrynn** » Fri Jun 04, 2010 7:07 pm

I have no picture but I do have a question about some life I saw at rosario. While scooting around some rocks and eel grass I noticed several clouds of micro fish like plankton, these formations were comprised of several thousand of these guys. I saw atleast 10 of these groups some so thick I could feel them smack across my face.

I also noticed some red in the groups but I think it was just the vegetation around them. Also another note, they reminded me of bee swarms...except underwater.

My question is this, what would be in groups like this? It reminded me of plankton or a shrimp but I could never get close enough to examine these guys because they would always scatter.

ljjames · Post by **ljjames** » Fri Jun 04, 2010 7:29 pm

krill!!!!!!

out in the straits during the right (wrong) time of year, they can actually swarm so dense around your light that it's actually ridiculous to try and bother diving....

I think Dan has a video showing them from out in the straits... can't remember if it's duncan rock vid or andalusia

http://www.nwdiveclub.com/viewtopic.php ... ia#p116692

Dashrynn · Post by **Dashrynn** » Fri Jun 04, 2010 7:46 pm

ljjames wrote:krill!!!!!!

out in the straits during the right (wrong) time of year, they can actually swarm so dense around your light that it's actually ridiculous to try and bother diving....

I think Dan has a video showing them from out at Duncan rock or seiku...

okay i saw the video and thats definitely how they were, except they seemed to be more compact and not as scattered.

I'm debating going back out there at high tide and scooting back out to this place whilst making video also. Surprisingly it was pretty cool out there except for the shallow depth and fear of mild boat traffic. Also saw some nice sized lings, and i think a cabazon but he zipped away before i could get a good look at him

ljjames · Post by **ljjames** » Fri Jun 04, 2010 8:08 pm

earlier in the season maybe? still little and traveling in packs....

brownick · Post by **brownick** » Sat Jun 05, 2010 11:04 am

The small crustaceans in Dan's video look more like mysids (opossum shrimp) rather than krill. Krill often have a little bit of red in them so they still might fit the description of what you saw. Here is a picture of a swarm of mysids I took at Koitlah Point out near Neah Bay. I have yet to get lucky enough to photograph krill while diving.

Greg Jensen · Post by **Greg Jensen** » Sat Jun 05, 2010 2:29 pm

Any big swarms that you see in shallow water in the daytime are almost certainly mysids- that's what is out at Sekiu most of the time, and we were in a ton of them a couple weeks ago at Rosario. The only time I see krill is on night dives in areas where it gets deep fairly quickly. They tend to be a little larger and are much stronger swimmers than mysids- they propel themselves using the appendages on their abdomen (pleopods or 'swimmerets') whereas most mysids don't even have pleopods. They're very, very different- once you've encountered both you'll never get them confused again.

Huskychemist · Post by **Huskychemist** » Sat Jun 05, 2010 6:47 pm

Alright, here's a picture from 2006 at Redondo, below the pier. The swarm was so thick it was hard at times to see, as the swarm absorbed the light from the camera.

It was cool and weird all at the same time.

So...krill or mysids? And it's been too long, so I don't remember what kind of swimming they were doing. They were reddish, so at the time I thought krill.

Any thoughts?

Thanks.
Lowell

brownick · Post by **brownick** » Sat Jun 05, 2010 7:11 pm

I'm going with krill on that one, Greg?

dwashbur · Post by **dwashbur** » Sat Jun 05, 2010 7:23 pm

I thought the subject line was going to the the intro to a joke...

Sockmonkey · Post by **Sockmonkey** » Sat Jun 05, 2010 7:52 pm

Punchline: The Lollypop Guild
(I thought the same thing)

Someone was recently talking smack about not coming to nwdc to learn.... This thread... And Greg J (as usual) proved them wrong.

Aloha hard,

-Eric

dphershman · Post by **dphershman** » Sat Jun 05, 2010 9:02 pm

Greg Jensen wrote:Any big swarms that you see in shallow water in the daytime are almost certainly mysids- that's what is out at Sekiu most of the time, and we were in a ton of them a couple weeks ago at Rosario. The only time I see krill is on night dives in areas where it gets deep fairly quickly. They tend to be a little larger and are much stronger swimmers than mysids- they propel themselves using the appendages on their abdomen (pleopods or 'swimmerets') whereas most mysids don't even have pleopods. They're very, very different- once you've encountered both you'll never get them confused again.

so these were mysids that I saw at Edmonds?

Greg Jensen · Post by **Greg Jensen** » Sat Jun 05, 2010 9:29 pm

The Redondo shot is krill (you can see the pleopods on the one standing on its head, straight in front of the light) and the Edmonds picture is of mysids. The inset nicely shows a couple with marsupiums (brood pouches)- krill never have these.

Dashrynn · Post by **Dashrynn** » Sat Jun 05, 2010 9:46 pm

That last picture kinda reminds me of the ones i saw at rosario...but then again i didn't get a good look. Also that's an awesome picture! Wow!

Greg Jensen · Post by **Greg Jensen** » Sat Jun 05, 2010 10:28 pm

Here's a mysid picture I took at Rosario a couple weeks ago- this is NOT the kind that forms the big schools, these are larger and hang out by themselves or in loose groups of a half dozen or so. This kind has small pleopods but they don't use them for swimming; you can just barely see them scrunched up against the abdomen. Mysids swim by fluttering the feathery outer branch of their legs (structures called exopods).

Northwest Dive Club