Scientists are discovering more than two new species of fish a week on average in their survey of the world's oceans.

Researchers from more than 70 countries are collaborating on the world's first Census of Marine Life, a $1-billion US project due to report findings in 2010.

"We have barely skimmed the surface," said Frederick Grassle of Rutgers University, who chairs the scientific steering committee for the census. "Humans have explored less than five per cent of the world's oceans."

To date, scientists have described about 230,000 marine species, including 106 new species of marine fish that were added to the database so far this year.

The newcomers include a striped goby that lives off Guam in the Pacific, and two types of octopus in the Antarctic.

Acoustic tags revealed rare green sturgeon 1,000 kilometres north of their spawning grounds in California. About 30 of the fish were found off northern Vancouver Island.

Researchers are also using new techniques such as sophisticated filtering and gene sequencing to find new microbial species.

On Monday, they released a map showing what has been catalogued so far in the Ocean Biographic Information System database.

The locations of species ranging from microbes to whales are represented by dots on the map.

Researchers hope the project will improve their understanding of the oceans and help them to monitor overfishing and climate change.