Sable Gully depths hide new giant file clam species

A new species of giant file clam has been scooped from the deepwater floor of Sable Gully, a huge underwater canyon and marine protected area 220 kilometres off the coast of Nova Scotia.

Protected underwater canyon Sable Gully 'keeps yielding its secrets'

A new species of giant file clam has been discovered in a deep underwater canyon Sable Gully, about 220 kilometres off Nova Scotia. (Submitted by the Department of Fisheries and Oceans)

Canadian scientists have identified a new clam species off the coast of Nova Scotia in a case that stretches back three decades, involves DNA testing and is proving the ecological variety contained in Canada's first marine protected area.

The discovery is a new species of giant file clam, although the name might be misleading as the mollusk is nine to 15 centimetres long.

"A very large specimen could fit in the palm of your hand," says Ellen Kenchington, a federal fisheries research scientist at the Bedford Institute of Oceanography.

It's a big deal for researchers at the Bedford Institute of Oceanography and the Canadian Museum of Nature who published their discovery in the journal Zootaxa.

"Its not something that happens everyday," says Kenchington who has been involved in two such discoveries in a 25-year career.

Mysterious species resembles scallop

The file clam, which resembles a scallop, was first discovered 30 years ago off Newfoundland by Jean-Marc
Gagnon when he was a graduate student.

"Originally, we assumed it to be a European species," says Gagnon who is now curator of invertebrates with the Canadian Museum of Nature.

The breakthrough came in 2007 when DFO scientists on the Coast Guard ship Hudson used a remotely operated vehicle to collect samples from the deepwater floor in the Gully, a huge underwater canyon and marine protected area 220 km off the coast of Nova Scotia.

This benthic octopus is one of the creatures discovered in surveys of The Gully. (DFO)

"We didn't necessarily know what we were seeing for sure," says Kenchington, an expert who specializes in ecological regions found in the deepest waters.

"We brought it up and I looked at it and I thought it doesn't look like the European species because it was much more delicate than the European species which I had seen previously."

Fortunately on the trip, a graduate student was carrying out DNA extraction on deep-sea corals. Kenchington asked for DNA testing on the clam. Subsequent analysis revealed a unique species.

Gully 'keeps yielding its secrets'

It has been given the scientific name Acesta Cryptadelphe which means cryptic sibling, a reference to its European cousin.

Further research trips in 2010 found other specimens off Newfoundland and more in the Gully, which is proving a boon to scientists.

"It keeps yielding its secrets. Every time we go, we learn more," says Kenchington.

The largest underwater canyon on the Atlantic coast of North America, the Gully lies 45 kilmetres east of Sable Island and is about 40 kilometres long and 13 kilometres wide.

Federal fisheries scientist Ellen Kenchington says the new giant file clam species is one of the unique life forms that can be found in the Gully off Nova Scotia. (CBC)

It's home to the rare bottle-nose whale, and the giant blue whale which swims through the area during its annual summer migration.

Scientists have marvelled at the deep-sea corals, sponges, benthic octopus and the weirdly beautiful deepwater Dumbo octopus found there.

Kenchington says something like 40 species have been collected in the Gully that are either newly recorded in Canadian waters or are potentially new species.

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