Blog

19 September: The Rote Boat (Timor-Leste-Expedition)

By: Michael Hugill, Category: Science, Date: 20 Sep 2012

With their equipment finally arriving this morning, the marine scientists were able to have their first dive.

Timor-Leste Marine Expedition #53

Michael Hugill © Australian Museum

"This is why I do science," said Pat Hutchings, as she placed her habitat samples in the esky aboard the boat. "No more of that laboratory stuff for a little while, it's just great to be out in the field."

I heard variations of this from many of the scientists after their first dive today, all excited to finally be collecting samples from the coral locations they'd come to analyse. From just a few hours out at sea can come many months of laboratory work.

None of them, however, have done as much laboratory work as Pat. I would tell you exactly how long she's been working at the Museum but I think she'd probably kill me. And on that note...

It's time to be perfectly frank about collecting: when museum scientists speak of preserving specimens, they're not talking about keeping them alive, even though that is the ultimate goal. (Bear with me here.)

How and why must the flora and fauna captured on these expeditions be killed?

When it comes to fish, the how must be done as quickly and painlessly as possible, with Jeff Leis telling me the other day, only half-jokingly, that he puts fish to sleep. It must also be done with minimal environmental impact. How is this possible?

By using rotenone or 'rote' for short.

Rotenone is a plant extract that affects the uptake of oxygen in the gills of fish. It comes in a powdered form and was mixed with seawater in a plastic bag on the boat just before diving. Snorkelling above, I watched as small clouds were 'puffed' from the bag in, under and around the coral within the targeted area. The divers then set about picking up as many specimens as possible.

I'm told, interestingly enough, that rotenone was first used by Amazonian fisherman who placed it on the end of spears in order to stun fish.

Whether the rote anaesthetises or kills depends on the dosage. The reality is, on a trip like this, it's simply more efficient to kill the fish in the water, collect them into mesh bags and then put them on ice back on the boat.

Greg with a crionoid.

Non-fish specimens such as worms, crustaceans or crinoids (pictured above) are not necessarily collected with rotenone. Tools such as chisels are used to pry small pieces of habitat from underwater. They're then kept in bags of sea water until they can be returned to base for sorting. It's during that process that specimens come to be placed in ethanol.

Ethanol stops the specimen from rotting and also preserves it such that genetic analysis and other studies can be performed. Which leads us to the why.

Why must specimens be killed? In other words, why not just take a photograph?

Processing the catch

To summarise Mark McGrouther's answer to this question: a photo isn't always enough. It might not show all the physical characteristics that having an actual specimen can. Also, some species of fish are never seen by divers and so it only through intensive collecting techniques that a truer picture of biodiversity can be painted.

And why collect at all?

Collecting specimens and objects is a core part of any natural history museum. Our webpage on the matter makes an excellent point: collections can be compared with libraries, except it's specimens that are available instead of books.

Preserved species are borrowed, studied and returned with the information from each new study added to the records, increasing our knowledge and understanding of them. (And having borrowable collections reduces the need for others to go out and collect their own.)

These taxonomic records form the building blocks of the study of nature, and are a key science on which others depend.

As this trip is the first comprehensive survey of marine habitats in Timor-Leste, it's the Museum's goal to make records that could assist with the develepment of a protected area network, hopefully enabling the preservation of the habitats from which we took just tiny fragments.

Follow our expedition on the Timor-Leste Expedition homepage and look out for updates from our Facebook and Twitter accounts.