Monster starfish: NIWA scientists Sadie Mills and Niki Davey holding up giant Macroptychaster sea stars measuring 60 cm across.

Credit: John Mitchell/NZ IPY-CAML

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SYDNEY: A survey of New Zealand's Antarctic territory has unearthed novel marine creatures living in the icy depths of the Ross Sea. The haul of 30,000 specimens includes giant starfish half a metre across, and weird predatory sea squirts.

Scientists aboard the New Zealand research vessel Tangaroa made the discoveries during an eight-week survey, which returned to Wellington last week. The creatures include eight new molluscs, and eight fish species that may be totally new to science.

Harsh environment

"It was great to be able to collect a huge range of species from such a harsh environment," said John Mitchell, voyage leader and marine geologist at the National Institute of Water and Atmospheric Research (NIWA) in Wellington.

"Numerous new species [were found] and that is even before our scientists get to fully examine the catch – which is bound to show up further new species," he said.

Outsize sea creatures unique to polar waters were amongst the other samples dredged up from the depths: giant starfish and sea spiders, jellyfish with four-metre-long tentacles, and rare colossal squid specimens.

NIWA scientist Malcolm Clark described how meadows of crinoids (sedentary animals also known as sea lilies), enveloped some of the seamounts his team surveyed.

"The high abundance of bright yellow crinoids on stalks 20-centimetres-high, offered a spectacular sight. These invertebrates form a primitive group, restricted to relic-type environments where very little has changed for millions of years. They are often considered living fossils," said Clark.

"A seamount is a very rough and hostile environment, and yet some of the communities we observed were spectacular," he added.

Small brittle stars, closely related to starfish, were also found to carpet the sea floor in surprising densities. These tiny creatures usually feed off the seabed but images the team collected show their tentacles stuck up almost vertically – an adaptation which likely allows them to capture food floating in the currents around the seamounts.

Largest ever survey

The major biodiversity study was New Zealand's largest ever Antarctic marine research program, undertaken under the auspices of two current international projects: International Polar Year and the Census of Antarctic Marine Life. The 44 scientists and crew on board the vessel were forced to endure the worst ice conditions in the Ross Sea for over 30 years, battling with the elements to make the new discoveries.

The survey examined a wide variety of life – from viruses and bacteria to blue whales – using high tech cameras developed specially for the project. Video feeds and high-resolution images captured scenes ranging from the surface right down to the rarely visited seabed, at depths of up to 3.5 kilometres.

A mystery animal of the deep, more than 50 cm long, photographed in the northern Ross Sea. Possibly a predatory tunicate (relative of sea squirts). A small isopod crustacean is perching on top." [Credit: DTIS camera, NZ IPY-CAML]

"It was amazing to see these strange and new species in the flesh from our sampling and then to also see them in their natural habitat on video," said Mitchell.

"We have observed all kinds of new behaviour and interactions between different species," added Clark. He hopes that the study of the relationships between these marine species and the impact of human activity on them will be a future direction for research.

Despite the frigid temperatures and hazardous conditions, the Tangaroa completed its voyage with a six-day return journey to New Zealand last week.