Copepod? Isopod? Octopod?

I'm sure that many of you may have seen these before, usually as you are descending on a dive. I've seen them in the Caribbean and South East Asia, so I'm presuming they are pretty much everywhere......but what are they exactly? Any info welcome

[vimeohd]58293792[/vimeohd]

Thanks,

Kaj

?Fish Scales?

?Fish Scales?

Fish have scales These look like, if you've ever seen one, shiny blue fish scales floating through the water, until you notice that they move....

First of all, awesome footage, as always!

As I have mostly seen these on sunrise dives I always thought that it was some sort of bioluminescence, but as you say, it really looks like it moves!

From what I can see it is extremely thin and glass-like, it doesn't look like there are any organs, appendages or anything, shape looks like that of a copepod but to be honest, I'm just guessing! To me it looks like it is see-through and on occasion reflects the surface light giving it the blue color.

I hope someone will be able to ID this as I am really interested to know what these things are!

Happy bubbles, Morten!

Hi, it is an isopod, but haven't bothered figuring out which family.

The first seconds show a live specimen moving, while the rest of the video likely shows an empty exuvium (the empty shell). Appendages are visible if you look thoroughly on the video (not reflecting the light).

Examples of some isopods:

www.flickr.com/photos/odonataman/7366212230/

www.flickr.com/photos/okinawaphotos/7948006250/

Jonas

Close. it's a male Sapphirina copepod. The females are shaped differently, usually have 2 egg sacs at the rear, & are transparent. Males are also transparent but there are structures throughout the exoskeleton that work like prisms when the light strikes just right. That's what makes it appear & disappear. Lot of species in the genus; at least some of them are predators or parasites of salps at some point during their lives.

ImageQuest has nice shots of the sexes & more info.

http://www.imagequest3d.com/pages/articles/articleofmonth/sapphirina/sapphirina.htm

Thanks Leslie. It was exciting to find one that I could film, albeit the molt of a male