TRANSCRIPT

NARRATION
Researching creatures underwater is always subject to the vagaries of sea conditions. So it doesn’t always go swimmingly…

Ruben Meerman
We’re about to head just out there, and with a bit of luck, we’ll see some weedy seadragons. David and his team have been working on them for about eight years and we’re going to see what they get up to underwater.

NARRATION
Hopefully this swell isn’t making the water down below too murky.

Prof David Booth
It gets bigger, we’ve been in in slightly bigger, but any bigger than this we’d probably think twice. The main thing is the surge down below, it should be alright.

NARRATION
Well the visibility in the water is down to a couple of metres at best. David can’t conduct his research in these conditions. So sadly we’ve decided to abandon this dive.

NARRATION
Fortunately David’s had better luck on previous dive expeditions.


Prof David Booth
Well weedy seadragons, I’ve known about them for a long time and they’re a very iconic fish.

Prof David Booth
And it’s quite shocking to realise how little is known about them in their natural habitat. A few bits of work had been done but even basic things like their growth rate, how long they live, how far they move, was just completely unknown.

Ruben Meerman
So where does the weedy seadragon fit as a species, where does it sit?

Prof David Booth
There’s two dragons. There’s the weedy, the one we’re studying, and also the leafy, an even more bizarre looking creature. And there are the only species in their respective genera so there aren’t any similar species worldwide actually, so Australia,ah, we have them all.

Ruben Meerman
Fantastic, we’re unique.

NARRATION
Seadragons, seahorses and pipe fish belong to the same family, so they share many intriguing behaviours and physical attributes.

Prof David Booth
They have a long tubular snout, which they use to grab little prey items, little shrimps and things. And they also have this curious habit of the males brooding the eggs. And in the case of sea horses they brood them in a pouch, but in the case of seadragons the males have the eggs attached to the outside of the tail.

NARRATION
So the men are left holding the babies.


Ruben Meerman
What is it that you’re trying to establish with this study?

Prof David Booth
To understand how to manage any species in the wild we need some basic ecology. Basic what we call population demography. We need to know how fast the animals grow, that can tell us information about when they reproduce. We also need to know how long they live, seahorses maybe four to five years and sea dragons six or seven years. So if the animals for whatever reason disappear from a site, we know that it's going to take a long time for recovery of that site.

Ruben Meerman
So where did this guy come from?

Prof David Booth
This one was found deceased at the site at Kurnell.

Ruben Meerman
And so what’s going on with the tagging system, how are you doing that?

Prof David Booth
Well this is probably a good way to illustrate how we tag.

Prof David Booth
We inject the animal with a small amount of this fluorescent elastomer under the skin. So with a couple of different colours and several different locations we can get maybe two or three hundred tag combinations so each fish has its own tag.

NARRATION
The non-toxic paint becomes highly visible under ultra-violet light.

Prof David Booth
We go down and shine the light on them and we know that’s seadragon number 32 or whatever, and then we just survey repeatedly over the years.

Ruben Meerman
So what have you found so far about their lives?

Prof David Booth
Well for a fish the size they are they don't move very much. And interesting, a lot of large fish don’t move very far. It’s the babies that move. And so typically with these guys, they might move about 100 metres or so in their adult lives.

NARRATION
Seadragons are quite a widespread species. They’re distributed from north of Sydney all the way around the south coast into Western Australia. On most reefs that are suitable you’ll find a few seadragons.

Prof David Booth
We’ve noticed through the years some of the sites there’s been a bit of a decline in numbers. It’s hard even if you’re working on a species for six or seven years, it’s hard to really put your finger on whether this is a global decline or whatever. We're going to keep an eye on them.

Prof David Booth
I think it’s more a habitat thing. Botany Bay is a very urbanised bay. But the mouth of Botany Bay is in pretty reasonable shape. There’s all sorts of potential threats with development that we’ve got to keep an eye on, but provided we can keep those kelp beds in reasonable condition, I think the seadragons will benefit and thrive.

NARRATION
So, with a bit of luck, the next time David and his crew venture down into the world of the seadragons, the water conditions will be more favourable. We’ve still got a lot to learn about these surprising sea creatures.

Story Contacts

Professor David Booth
University of Technology, Sydney
Dept of Environmental Sciences
Building 4, Level 5, Room 5.45B

Jaime Sánchez-Cámara (underwater archive footage)
Aquadec Aquariums S.L.
Pol. Ind. El Vadillo. C/ Santo Domingo s/n
18600 Motril, Granada, Spain

Related Info

Sydney Institute of Marine Science (SIMS): Weedy Seadragons

Australian Museum – Weedy Seadragon

Australian Museum – Leafy Seadragon

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