Exploring the Deep Sea Canyons of Ningaloo

Main Club September 2020

The Faceless Cusk. The goggle-eyed Cockatoo Squid. Glass sponges. A living “swirl of spaghetti”. These are some of the truly weird and wonderful creatures that we met at the September meeting.

Our speaker was Dr Nerida Wilson, Research Scientist at the WA Museum and Manager of the Molecular Systematics Unit. She is interested in the evolutionary relationships between organisms, especially between marine animals.

Over half the planet consists of deep oceans, but very little is known about the organisms that live there. Very few people have visited the abyssal plains that are 2000 to 3000m deep, let alone the oceanic trenches, and it takes hours for manned vehicles to reach those depths and return. So to study the organisms at these depths off the coast of WA, a multidisciplinary study was proposed, using the Schmidt Ocean Institute’s RV Falkor, and remotely operated underwater vehicle (ROV) SuBastian.

As well as partnering with the Schmidt Ocean Institute, the WA Museum worked with Curtin University, Geosciences Australia and the Scripps Institution of Oceanography to study the Cape Range Canyon off Exmouth. This is one of 95 canyons that incise the continental shelf of Australia.

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Nerida showed us pictures and videos of some of the extraordinary creatures that were found, such as giant hydroids, swimming worms, a weird-looking blind fish called the Faceless Cusk, a large, flashing squid and the giant siphonophore, like an enormous swirl of spaghetti.

The four prongs of the project were a biodiversity study, a complementary eDNA survey, bathymetric mapping, and deploying autonomous reef monitoring structures. (These are like “bee hotels” to collect cryptic animals). An eDNA survey involves taking environmental DNA samples from the water to ascertain what organisms may exist in that locality. (Organisms expel DNA into the water.)

Solitary hydroid: A rare hydroid discovered thousands of metres down on the sea floor of Cape Range Canyon (approx. 1 metre tall). It is the first time this amazing animal has been filmed and collected in Australian waters.

The scientists, ship’s crew and technicians, work together on the ship, watching live streaming of what this “robot on a string” can “see”, in its narrow field of view in the dark ocean. It can even focus on tiny animals with its “crisp” camera. They sometimes witnessed predatory encounters and discovered who eats who. The ROV has “arms” to pick up samples. In the on-board laboratory, the organisms are studied, classified and described, type specimens are made of any that are new to science, and tissue samples taken for DNA analysis.

The scientists, ship’s crew and technicians, work together on the ship, watching live streaming of what this “robot on a string” can “see”, in its narrow field of view in the dark ocean. It can even focus on tiny animals with its “crisp” camera. They sometimes witnessed predatory encounters and discovered who eats who. The ROV has “arms” to pick up samples. In the on-board laboratory, the organisms are studied, classified and described, type specimens are made of any that are new to science, and tissue samples taken for DNA analysis.

Nerida said that many of the finds were unexpected, and many had never been seen before by humans. Her enthusiasm was evident in the talk. “It’s all exciting”, she said.

Mike Gregson

Note: some videos of the creatures can be seen by searching YouTube for Ningaloo Canyons.