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NATURE

Researcher discovers 4 new fish in Antarctic

The Antarctic gravelbeard plunderfish (Artedidraco glareobarbatus) was collected at a depth of 130 meters near Franklin Island in the Ross Sea   

March 11, 1999
Web posted at: 4:45 PM EST




An Ohio University scientist has discovered four new fish species in the frigid Antarctic waters, a surprise to many scientists who believe the waters there are too cold to sustain diverse life.

Joseph Eastman, an anatomist who made his discoveries aboard the Nathaniel B. Palmer, an icebreaker in the National Science Foundation's polar research fleet, discovered the new species almost by chance.

Eastman was studying the anatomy of buoyancy and how it evolved in Antarctic fishes. During trawls of the Ross Sea, Eastman found the new species -- which includes the first identification of a new species in the genus Artedidraco in 80 years.

"It wasn't my intention to look for new species," he noted.

Eastman says the discoveries confirm his hypothesis that Antarctica's frigid seas are a world-class evolutionary laboratory.

"Antarctica is under-appreciated as an evolutionary site," said Eastman. "The oceanic waters surrounding the continent are a natural evolutionary laboratory comparable to the Hawaiian Islands or Lake Baikal in Russia."

Eastman told NSF that in his 20 years of experience he has found that "as far as bottom habitats are concerned, sponge beds in Antarctica are the equivalent of coral reefs in the tropics; sites of high fish diversity."

Eastman's research indicates that Antarctic fish have geologically evolved to fill ecological niches that unrelated species would otherwise occupy. This is the only known example of an adaptive radiation in marine fish, according to Eastman.
The Antarctic brainbeard plunderfish (Pogonophryne cerebropogon) was recently collected at a depth of 300 meters in the Ross Sea   

In the past, scientists have found fossil evidence indicating that thousands of years ago a variety of species used to occupy ecological niches in Antarctic waters, most likely when the water was considerably warmer. But Eastman said that many scientists wrongly assume that because the relatively shallow coastal waters around the southern continent are now so cold, they also must be relatively barren and uninteresting in an evolutionary sense.

In warmer waters, fish species live in all levels of the water column, prompting a greater diversity of species throughout the ecosystem. Along the Antarctic shelf, where waters are usually less than 500 meters deep, the variety of species differs greatly.

In Antarctica, 95 species of notothenioids, all derived from bottom-dwellers without swim bladders, dominate all habitats. Over evolutionary time, some of these fish have experienced an increase in body fat and are able to live permanently in the water column, rather than on the bottom, according to Eastman's research.

Polly Penhale, who oversees medical and biological research for the U.S. Antarctic Program, said that Eastman's findings indicate that "future research is likely to lead to a greater appreciation of biodiversity in the polar regions."

For more information, contact Polly Penhale, NSF, (703)306-1200, email: ppenhale@nsf.gov.

Copyright 1999, Environmental News Network, All Rights Reserved


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RELATED SITES:
National Science Foundation: Polar Research
Ohio University
Dr. Joseph Eastman
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