More than 100 species of sharks and rays have been classified and named as new species, including some that had been discovered as far back as the early 1990s.
The new namings and classifications are the result of an 18-month Australian project using DNA analysis to clarify the identity of closely related species.
The new species include:
The endangered Maugean Skate (Zearaja maugeana), which lives only at the southwestern tip of Tasmania. It is closely related to an ancestor that lived off southern Australia some 80 million years ago. A critically endangered gulper shark known as the Southern Dogfish (Centrophorus zeehaani), which is endemic to the continental slope off southern Australia. The Northern Freshwater Whipray and the Northern River Shark, which are among the largest freshwater animals in Australia at more than 6 feet (2 meters) long. Until recently these were confused with similar marine species.
"Additional taxonomic information like this is critical to managing sharks and rays, which reproduce relatively slowly and are extremely vulnerable to over-fishing and other human impacts," said project leader Peter Last of the nation's top research agency, CSIRO. "Their populations are also sensitive to small-scale events and can be an indicator of environmental change."
Sharks and rays play a vital ecosystem role as top predators, culling weak or dimwitted members of other species.
"Take them away and what does it mean for the rest of the ecosystem?" said team member William White. "We can't understand possible implications unless we know what species we're dealing with."
Sharks are also sensitive to small-scale events and can be an indicator of environmental change, the researchers said.
Most of the sharks and rays were identified but not fully described in 1994. They new names and descriptions will be published in book form in 2009.
DNA marine probe finds more jaws than before
Andrew Darby, The Age 19 Sep 08;
IT'S always nice to know there are more sharks around than you think, particularly if you're a marine scientist looking for new species.
"They have been much maligned," said Peter Last, a CSIRO taxonomist who announced yesterday that Australia had 100 new shark and ray species. "There are many more shark-eating men, than man-eating sharks."
These creatures had character, Dr Last said. "A lot of them are quite inquisitive, tactile. They do have a puppy-like feel.
"But they are key predators in the oceans. Without sharks and rays, the whole food chain is compromised to some extent."
His team found that Australia's wealth of shark and ray species numbered 300, about half of which are only found in these waters. "With the exception of Indonesia, we have the richest shark and ray fauna on the planet," Dr Last said.
The finding that Australia had many more species than thought owes much to revolutionary molecular identification techniques. "They've turned the task of species identification upside down."
Previously a species had to be described by a scientist who observed its distinctive qualities. Now DNA identification such as is used in the international Barcode of Life project sets a global standard.
So although scientists knew that there was an angel shark, with big "wing" fins, which scouted the seabed off eastern Australia, subtle differences in those in NSW waters were unrecognised. The CSIRO work confirmed that the NSW angel shark was a separate species.
Likewise the harmless northern river shark was separated from the aggressive bull shark that accounts for many attacks on people in harbours and estuaries. And the spectacular orange-spotted leopard ray of northern Australia was different again from its Indian cousins.
For some species, identification will help ensure survival.
The southern dogfish, a blunt, metre-long shark, lives on a narrow band of heavily trawled continental shelf slope off south-east Australia. With an estimated 99% cut in its numbers over 20 years, it was recently listed as critically endangered.
The dark waters of Port Davey and Macquarie Harbour in south-west Tasmania provide the only known habitat for the modest, dinner-plate sized maugean ray. With warming seas under climate change, this habitat is threatened, Dr Last said. "This ray really hasn't changed much in 80 million years. It would be catastrophic to see it just go in the blink of an eye."
The work to date suggested there may be more sharks and rays left to discover, he said.
Scientists name 100 new shark and ray species
Michael Perry, Reuters 18 Sep 08;
SYDNEY (Reuters) - Scientists using DNA have catalogued and described 100 new species of sharks and rays in Australian waters, which they said on Thursday would help conservation of the marine animals and aid in climate change monitoring.
More than 90 of the newly named species were identified by scientists in a 1994 book "Sharks and Rays of Australia" but remained scientifically undescribed.
One rare species of carpet shark catalogued was found in the belly of another shark.
The new names and descriptions will now feature in a revised 2009 edition of the book by Australia's peak scientific body.
The Commonwealth Scientific & Industrial Research Organization (CSIRO) said its cataloguing of the new species was critical for the management of sharks and rays, which reproduce slowly and are vulnerable to overfishing.
CSIRO scientists said sharks and rays as apex predators play a vital role in the ocean's ecosystem and can be indicators of climate change.
"Their populations are sensitive to small-scale events and can be an indicator of environmental change," CSIRO team leader Peter Last said in a statement announcing the cataloguing.
Some of the new species named include:
* The endangered Maugean Skate shark, closely related to an ancestor from the Gondwanan period in Australia some 80 million years ago, found at the southwest of the island state of Tasmania. It is one of the only skates in the world found in brackish or freshwater and its survival could be affected by climate change, said the scientists.
* The critically endangered gulper shark or the Southern Dogfish which is endemic to the continental shelf off southern Australia.
* The Northern Freshwater Whipray and the Northern River Shark, which grow to over two meters (six feet) in length, and are among the largest freshwater animals in Australia. Until recently these were confused with similar marine species.
Environment group WWF-Australia said the cataloguing of 100 new species of sharks and rays would boost conservation moves to protect the marine animals.
"It is a major scientific breakthrough," said WWF-Australia fisheries manager Peter Trott. "We now need to know what changes in management are needed to conserve these animals."
Trott said confusion between separate species of sharks and rays meant that new, rare or endangered species may be mistaken for more common species and inadvertently taken by fishermen.
"We are literally fishing in the dark when it comes to sharks and rays. In many cases we simply do not know what species we are plucking from Australian waters, Trott said in a statement.
(Reporting by Michael Perry; Editing by David Fox)
More links
- Over 100 new sharks and rays classified on the CISRO website