What the heck are these little red wormy guys?

[Ryffel]

Night dive last night, SoCal, Shaws Cove, Laguna Beach to be exact. Red, fast swimming worm-like creatures swarming around our lights. About one inch in length, maybe 1/8 inch in diameter, red cylindrical body with a white head. I have only seen these once before. Please help me identify them.

Thanks.

 

[Rick Murchison]

Oviously I can't be positive without seeing what you're seeing, but from your description they're what we call "blood worms." Sorta have a pinkinsh tint to the red color; corals eat 'em gleefully at night.
Rick

 

[Machiavelli]

Actually that sounds alot like an epitoke swarm. Basically a bit of tail filled with egg or sperm thats been released from a benthic polychaete. They release them en-masse, usually at night time in order to make more polychaetes.

 

[LeslieH]

As Machiavelli said, they're probably epitokes. I suspect they're nereid (often called ragworms or pileworms in the bait business) epitokes which consist of the whole animal rather than just the tail (more common in syllid & eunicid polychaetes). It's a neat process - the internal organs are absorbed while the body fills up with eggs or sperm, the parapodia (lateral appendages used for locomotion) enlarge & become paddle-shaped and the eyes enlarge. The bright red color comes from the eggs/ sperm packing the body. Swarming normally occurs around full moons just like coral spawning. This image shows a nereid epitoke -- Ryffel, did your guys look like this?

the worms commonly known as blood worms - glycerids and arenicolids - usually don't swarm in the same manner.

 

[jlyle]

As Machiavelli said, they're probably epitokes. I suspect they're nereid (often called ragworms or pileworms in the bait business) epitokes which consist of the whole animal rather than just the tail (more common in syllid & eunicid polychaetes). It's a neat process - the internal organs are absorbed while the body fills up with eggs or sperm, the parapodia (lateral appendages used for locomotion) enlarge & become paddle-shaped and the eyes enlarge. The bright red color comes from the eggs/ sperm packing the body. Swarming normally occurs around full moons just like coral spawning. This image shows a nereid epitoke -- Ryffel, did your guys look like this?

the worms commonly known as blood worms - glycerids and arenicolids - usually don't swarm in the same manner.

It's wonderful having you around, Leslie! I was hoping you had seen Ryffel's post. Thanks for the information. I learn something new every day.

You, too, Machiavelli!

 

[Machiavelli]

I would watch small-scale epitoke swarms in my reef tank back when I had it. Fun part was shining a flashlight into the tank and watching them all come straight towards it. This was also the best time to try and spot the enormous foot-long bristleworms and try to photograph them.

I vaguely recall reading about an epitoke swam in Florida, I believe, which happened at night and featured epitokes which either glowed or flashed in the dark. Any idea what that might have been? Apparently the big glowing swarm made quite a sight in the full moon.

 

[LeslieH]

It's wonderful having you around, Leslie! I was hoping you had seen Ryffel's post. Thanks for the information. I learn something new every day.

You, too, Machiavelli!

:kissykiss

There's a genus of syllid polychaetes called Odontosyllis. Several of the species are known to be bioluminescent & swarm in huge numbers right after the full moon. In fact, 500 years ago Columbus saw bright patches of light at night as he approached the Bahamas which is thought to have been produced by these worms. The ones off Floridae are Odontosyllis enopla; a similar species off Belize is O. luminosa - this might have been the one Columbus saw.

As the females swim up to the surface they emit a bioluminescent substance which glows steadily. The males below them flash in response then follow the females up to the surface. They circle around each other releasing eggs & sperm (also bioluminescent) then return to the bottom. Meanwhile fish & other organisms are doing their best to eat as many as possible but there's a catch - the glowing substance is apparently toxic! Fish that eat it can go into spasms & become paralyzed. Worms are just so wildly wonderful........

 

[Ryffel]

Yes Leslie, that picture looks very similar to the ones I saw. The full moon was out and they were swarming all over. I had my light on a large green anemone and some of the epitokes went right in. I didnt notice anything else feeding on them.

 

[SubMariner]

Wow.. great info.

Can we keep her.. can we.. please, Mom?

Never can have too many fishy-type experts IMHO.

 

[LeslieH]

FISH!!!!!! :broken_he :crossbone :kopfab: !!!!!!

And I mean that in a loving and supportive way........