(spider legs clacking)
- [Speaker 1] Oh wow, what's this?
- What is this? - Oh my god, look at that.
- You might remember this fascinating sea spider video
from April 2022 while OET was exploring the Kingman Reef
and Palmyra Atoll region of the Pacific Remote Island
Marine National Monument.
- [Speaker 2] Is that another dinner plate-sized spider?
- [Speaker 3] It's certainly pretty big.
It's 20 centimeters.
Something like this or so.
- [Speaker 2] Yeah.
- What we thought was a video of sea spiders matching pores
has been confirmed to be likely the first time
humans have witnessed these deep sea sea spiders mating.
To learn more about this amazing sighting,
I connected with sea spider expert Georg Brenneis
from the University of Vienna in Austria.
Thank you for joining us today, Georg.
We're really excited to have you talking with us here
at Ocean Exploration Trust about these sea spiders.
Could you tell us a little bit about yourself
and your background with these creatures?
- My name is Georg Brenneis.
I'm a zoologist and developmental evolutionary biologist
working at University of Vienna.
And I'm working for a long time by now,
more than 10 years on sea spiders.
I then saw this amazing video of yours.
- [Speaker 4] Yeah, this is-
- [Speaker 2] This might be reproduction here, huh?
- [Speaker 4] Yeah, based on Dr. Google.
It's looking like that's what it is.
- So I was extremely excited just seeing this
for perhaps not obvious reasons, but I will try to explain.
- What's going on in the video,
For those of us who don't have
extensive sea spider knowledge?
- What we are seeing here are two very large sea spiders.
One sits on top of the other.
We see them kind of from behind.
And the very interesting thing is
that you can actually also see more than just the legs.
In the very center, there are these reddish, angled,
slim appendages that are very close to the sea floor here.
And one of them to the left,
this is one that belongs to the lower animal
which is a female, from what we can tell.
And this animal holds in this appendage
which we call the ovigers, eggs.
And the individual on top,
where the same appendage is actually locking
under the female so that it doesn't get away.
So sometimes you can also see that they move in sync,
up and down during the video.
So what we are observing is, to my knowledge,
the very first time a mating behavior
of this particular group of very large,
so to say, giant sea spiders, the colossendeis,
that has been never recorded before anywhere,
although we know them for more than 150 years
and people have been looking for that.
So it's very unique.
I'm quite excited seeing this.
- So what is it about this video that is so exciting?
- First of all, it's a unique observation.
I can say that a already right now.
So what we see here are two sea spiders that are mating.
- [Speaker 4] Sea spiders mate
by using the genital pores in their legs.
The male sea spider climbs onto the female
and the pair adjusts until the pores are aligned.
- But these are not just any two sea spiders
that are mating.
So we know sea spiders now for quite a while.
This particular group we'll see in the video
is called the Colossendeis.
And the Colossendeis, the name suggests is
they're large-sized animals.
They're the largest among the sea spiders.
And weirdly enough, we have no knowledge whatsoever
about the reproduction and about their life cycles.
- [Speaker 4] Has this been documented before?
- [Speaker 3] We'll find out.
It's definitely something we'll have to reach out
to specialists about.
Great, great, yeah.
- So at this stage, people were also believing
they have a completely different reproductive biology.
And now you come along and you have this video
and that shows a mating.
What we don't have yet and that's something...
I had some tears in my eyes when I saw that the clip ends.
We don't know what happens with the eggs afterwards yet
because it could still be that they put them
on the sediment after they're done
or they put it on some invertebrate host that we don't know.
So that's a one-time shot
that you actually had there with this.
Hopefully it doesn't remain this one-time thing.
But it's really amazing.
- So what's next for this research
or for sea spider research in general?
- One thing that I hope having seen the video
that, I don't know, expeditions that use ROVs
and do all this very important monitoring,
they actually have some more luck
and locate these kind of the areas
and the events and document them.
- Thank you for speaking with us today
and to all of you watching,
thank you for keeping updated
on this amazing scientific discovery.
And we hope to see more sea spiders
and all sorts of things as we continue
to explore the ocean's depths
in the Central Pacific and beyond.
And if you wanna stay up to date on everything we're doing,
follow along at www.nautiluslive.org
and of course, on all of our social media channels.