Blog

AM Expedition: South West Pacific

By: Madelaine Love, Category: Science, Date: 27 Jul 2017

This week AM scientist embarked on a voyage of discovery to document marine fauna in isolated southwest Pacific islands.

Nudibranch, Chromodoris cf. amoenum

Nudibranch, Chromodoris cf. amoenum
Photographer: Ian Skipworth © Auckland Museum

AM Collection Managers Steve Keable (Marine Invertebrates), Mark McGrouther and Sally Reader (Fish), Mandy Reid (Malacology) will join Research Scientist Elena Kupriyanova, Senior Fellow Anna Murray and colleagues from Auckland Museum and National Museum of New Zealand, to survey marine life in remote islands and reefs surrounding Fiji, Tonga, New Caledonia and Vanuatu, including places few scientists have ever ventured before.

“Our collections contain comparatively few specimens from sites in the southwest Pacific region,” Keable says. “We’ve selected locations in that area with high potential to provide new information on distribution patterns. It’s exciting to be involved.”

The team has previously collaborated with their counterparts from New Zealand on a number of expeditions. Together in 2011, they surveyed the waters of the Kermadec Islands (between New Zealand and Tonga), southern French Polynesia in 2014 and Tonga and Niue in 2015.

Mandy Reid, Sally Reader and Mark McGouther processing samples on the deck of the Braveheart. Photo © Auckland Museum.

On this voyage (funded by AMRI – the Australian Museum Research Institute – and the AM Foundation), the scientists aim to build on previous work recording the area’s biodiversity and determining the influence of oceanic currents on the biological connectivity across the South Pacific.

"We also hope to gain greater understanding of the evolutionary relationships between the fauna from these islands and the wider Pacific region, including eastern Australia,” Reid says.

For nearly two months, the Braveheart, a 39 metre ship will be their home. At any one time, up to 17 Australian, New Zealand and other international scientists will live on board, with a crew of five, one of whom doubles as a cook.

So what is a typical day like on one of these expeditions?

Reid summarises the morning routine: “We wake up at dawn to the sound of the hydraulics of the boat’s crane lifting inflatable boats from storage on top of the ship into the water for use during the day to go out to the reef. We eat a hearty breakfast, that is followed by a quick briefing from the expedition leader and the vessel’s skipper.”

The scientists prepare their dive gear and sampling equipment and are usually in the water before 8am for the day’s first scuba dive. Their samples include fishes and the substrates that invertebrates inhabit, such as algae, sediment or rubble. Some of the substrates are gathered using a device, hooked up to a scuba tank, that acts like a small underwater vacuum.

After the dive, they return to the Braveheart to process their samples.They first identify invertebrates into broader groups such as snails and crabs, then photograph and preserve them in alcohol or formalin for storage. They separate the smaller invertebrates from the substrates, often by washing or sieving. They also take subsamples for genetic analysis. Everything needs labelling and documentation.

Scientists can identify many fish to genus or species on board, but need to wait until their return to the museum to access literature, microscopes and experts to classify the many invertebrates.

“It’s essential to photograph as much of the material as possible because many creatures such as fishes can be red with orange stripes, for example, and once you preserve them they lose their colours and all turn brown. The colour pattern can be important for identification,” McGrouther says, while Reid adds that colourful slugs can look like pieces of used chewing gum when preserved.

RV Braveheart docked at Rapa Island on the Southern French Polynesia Expedition, 2014. Photo © Auckland Museum. 

After a midday lunch, the team heads out for another dive, returning for more processing and then dinner around 6pm.

The expedition leader and skipper also brief the team about plans for the next day and predicted weather conditions.

“After that, processing samples can continue well into the night,” says Keable. “We might do further sampling, such as using a light to attract invertebrates and fishes. We also need to fill out our dive logs and write up a summary of all samples collected that day. We’re rarely in bed before 11pm, while the ship’s crew work shifts around the clock.”

Not every day involves collecting. Sometimes it takes hours or days to travel between sites.

“The boat is a fantastic platform for research work but is not of the glamorous cruise ship variety, and its size means that we bounce about a lot – I admit I’ve lost my lunch a few times,” McGrouther adds.

Once the team returns to the AM, it can take months to identify all the samples, integrate them into the AM collection, make them available to interested colleagues around the world and learn of any new discoveries.

So far from discoveries made in the 2011 expedition to the Kermadecs, AM scientists have contributed to more than 20 scientific papers and produced over 300 new marine species distribution records for the area.