MARITIME CENSUS: There are more than 210,000 known life forms in the world's oceans, but this could be a fraction of the total number of marine species, according to early results from a marine census published yesterday.
Scientists from around the world are expected to complete the census of the world's oceans by 2010, when they hope to have a better understanding of the waters that cover nearly 70 per cent of the Earth's surface.
With nearly half of the world's population of 6.3 billion living along ocean coasts, experts say the big deep has been under-explored.
"The census is an attempt to level the playing field and I hope that by 2010 we will know as much about life in the oceans as life on land," said Ron O'Dor, a squid expert from Nova Scotia who is co-ordinating the census.
Scientists from more than 50 countries are involved in the $1 billion census, being sponsored by governments and a US foundation, and experts are meeting in Washington this week to plan the next seven years of research.
Just three years into the study they were making new finds weekly, at an average rate of 160 fish species per year, Ron O'Dor said. Those fish are not necessarily new species, but have been never been recorded by humans. Over 15,300 species of marine fish are now in the census data base and experts involved in the count expect the final tally to be roughly 20,000.
About 1,700 other animals and plants are also being catalogued each year and scientists estimate 210,000 marine life forms are currently known but the final number could be 10 times higher.
While new species are being documented, scientists are alarmed at how many species have died out, having been lost to overfishing, pollution or climate change.
Recent research on the depletion of sharks and other large predators suggests the size spectrum of marine mammals is shrinking toward the small, said Mr Fred Grassle, chair of the census steering committee. Large fish have been depleted by about 90 per cent in the past 50 years and fishing grounds are being destroyed by large fleets delving deeper. "By changing one part of the ecosystem, the whole food chain changes," warned Ron O'Dor.
The obvious challenge in conducting the census is the vast size of the oceans and complete darkness at lower levels miles below the surface - what scientists call the Dark Zone.
Among recent finds at this depth have been giant squid and massive red jelly fish with muscular arms. The squid swims so fast, it has been impossible to catch. Just as animal movements are tracked on land, scientists are tagging the movement of fish by attaching digital instruments to athletic fish from sharks and tuna to sea turtles.
Tagging fish leads to less duplication when counting species and provides an accurate record of movement.
Scientists are also interested in looking at masses under the water, called seamounts, and what species thrive there.
"People knew there were isolated islands under the sea but we are finding that 70 per cent of the species on one seamount are not found on another. The fact these seamounts are coming under increasing fishing pressure damages that habitat," said Mr Grassle.