Census of marine life discovers 6,000 species

A DECADE-LONG survey of life in the oceans has so far logged observations of about 30 million individual organisms in an online “digital address book”. It has also discovered an estimated 6,000 previously unknown species and identified hot spots and highways of marine life from shoreline to abyss.

Findings from the Census of Marine Life were announced yesterday at a conference in London that described life in the oceans as “richer, more connected and more altered than expected.”

The project, which involved over 540 expeditions and chalked up roughly 9,000 days at sea, engaged over 2,700 researchers from more than 80 countries to work out a baseline of ocean life abundance, where species are and how they are interconnected.

It looked at oceans past and present and used technologies such as tracking systems and genetic analysis to better understand marine life and predict its future.

One of the most eye-catching findings is the enormous biodiversity in the oceans; many of the previously unrecorded species that the project turned up are still awaiting formal description, according to Poul Holm, professor of environmental history at Trinity College Dublin and a member of the steering committee for the census.

“There was one expedition off west Australia where every third specimen that was taken out of the water was a newly defined species,” Prof Holm said.

“It was just amazing, the amounts of information are so huge from this effort that so far we have only been able to publish about one-fifth of the probable new species identified.”

Prof Holm headed the History of Marine Animals Populations in the Census, which trawled back through historical records – including naval logs, fisheries documents and even restaurant menus – to work out how abundant species were in the past.

Heavy fishing is not just a modern problem, noted Holm, who described how records show that even in Roman times humans were extracting about 100,000 tonnes of fish per year from the western Mediterranean.

“A lot of the [stock] declines happened very early on relative to modern industrial fishing,” said Prof Holm. “We know now that in the European North Sea the fishing pressure reached what would today be labelled total allowable catches already by 1870. That’s before the introduction of modern steam-powered vessels and modern winches.”

The decline in those stocks has continued markedly since then, with massive reductions in cod and ling abundance, but sustainable aquaculture could offer wild marine species a chance, according to Prof Holm.

“Although a lot of this is a pretty sad tale of us taking out enormous amounts of living matter, the oceans are very resilient,” he said. “In general because the oceans are so vast there will always be an opportunity for species to hide and given an opportunity they will be able to replenish and rebuild. We have lost tremendous wildlife in the course of fishing down the North Sea, and if we stood back and allowed the populations to grow again the likelihood is that the sea would sustain much larger populations than any of us would know of in living memory.”

The census work will continue, said Prof Holm, but there’s a need now to sort through what has been discovered so far.

“This has been a huge challenge, so we need to gather our strength and ponder the enormous amounts of information that we have.” And there’s still more to collect: according to experts at yesterday’s conference, about 20 per cent of the ocean’s volume remains unobserved for marine species. “For those people who are searching for life on other planets,” commented one scientist, “there is still plenty of work to do here.”