Mid-term marvels

A half-time report from an unprecedented audit of the oceans has discovered hordes of unusual creatures and new data on better-known species, forcing scientists to rethink their ideas about the world's marine life. Among the new organisms to be identified are tiny carnivorous sea sponges that engulf passing prey and single-celled animals that protect themselves by building football-like shells. The new species were spotted by two separate expeditions that set out to probe the little-known depths of the South Atlantic and Southern oceans. Scientists aboard the vessels say that up to 90 per cent of the creatures they encountered have never been seen before. And new data are also throwing light on the movements of commercially important and threatened species that may help with future conservation. All this effort is part of the Census of Marine Life, a 10-year project attempting to draw up details of life in the world's oceans, the most underexplored environment on Earth. Now, at the halfway stage, the census involves 1,700 scientists in 73 countries. Each month during the past year they added an average of more than six new species of fish to a major database — the Ocean Biogeographical Information System — which links 60 databases containing 8.4 million taxonomic records that include mammals, sea birds, corals, turtles and anemones. This number represents a 62 per cent increase from the 5.2 million records held in 2004. The new records continue to add remarkable finds: along the mid-Atlantic ridge researchers spotted swimming red sea cucumbers, while in the Arctic ocean they discovered red jellyfish that grow up to three metres long. The census now totals more than 40,000 species, including more than 15,000 fish, although researchers believe these discoveries represent only a small proportion of undiscovered species that exist in these environments. " We estimate that there are around 230,000 species down there and we want all of those documented by the end of the census in 2010. But that's a conservative estimate. We could well find a million new species by then, " said Ron O'Dor of Dalhousie University in Canada and leading researcher on the census. Key to the census of new species is a silent-running vessel called GeoSars, which carries the world's most sensitive sonar. The ship can detect creatures the size of a shrimp at a depth of three kilometres. The average depth of the oceans around the world is …