Two thirds of world's marine species still unidentified, study says

The vast world that exists beneath the surface of the ocean remains largely unknown to humankind, say experts working on an international database of marine species.

Of an estimated one million species that make their home in the depths of the sea, as many as two-thirds of them are still a mystery, says a study published this week in the academic journal Current Biology.

Canada has more coastline than any other nation on Earth — a staggering 200,000 kilometres-plus — and the nation's territorial waters cover more than 7 million square kilometres over three different oceans. Canada is a world leader in marine research, but even here the sea still holds many surprises, says Gerhard Pohle, acting executive director of the Huntsman Marine Science Centre in St. Andrews, N.B.

"There are an amazing amount of things, especially in the ocean, that we don't know in terms of biodiversity," says Pohle, who spent a decade taking part in an international Census of Marine Life, a decade-long project than concluded in 2010.

It was only last year that scientists published research that estimated there are approximately 10 million distinct species on Earth, Pohle said.

"It's staggering to think that as recently as 2011, we did not know how many species there are in the world by order of magnitude. The estimates were anywhere from three to 100 million species globally. That was it," Pohle says.

"I'm somebody who works on this and when I saw it, I couldn't believe it."

Catalogue of species

The article estimates there are roughly one million marine species. A World Register of Marine Species has catalogued 226,000 of them so far. As many as 72,000 more specimens have been collected and are waiting to be described.

"Knowing what lives in the ocean is fundamental to appreciate, care [for it] and protect it," said Ward Appeltans, one of the authors and the project manager of the Ocean Biogeographic Information System of UNESCO's Intergovernmental Oceanographic Commission.

"Having a single catalogue of all known marine species is like an index in a library. We can all start using the same species names, avoid confusion over names and make less mistakes."

The register provides an invaluable base line for ocean life.

"It is good though that there is increased interest in biodiversity," he said. "We are now not only looking at the stars, but also what lives on our planet. We can no longer neglect how much we depend on the ecosystem services and how each species contributes to the functioning of our biosphere."

In Canada, the world registry spurred the creation of the Canadian Registry of Marine Species.

The online, open-access databases allows scientists to focus on collecting and analyzing information, rather than cataloguing and maintaining disparate databases, said Claude Nozeres, a Quebec biologist who has worked for Fisheries and Oceans and contributed to both the Canadian and world registers.

Canada is a major contributor to the international database, he said.

One example is a large sea pen that lives in the Gulf of St. Lawrence that Nozeres said was forgotten for decades, until it was "rediscovered" in a federal Department of Fisheries and Oceans museum collection. The species has now been added to both databases.