PARIS (AFP) – Due to an 83-year-old error of classification, a species of European skate could become the first marine fish driven to extinction by commercial fishing, according to a study released on Wednesday.
In the 19th century, scientists identified two separate species of the once-widespread European skate, the flapper skate (Dipturus intermedia) and the blue skate (Dipturus flossada).
But an influential study in 1926 argued the two species were in fact one, which prompted a new name, Dipturus batis.
Since then, trawling has massively depleted all types of European skate stocks, with France accounting for more than 60 percent of landings.
New research, led by Samuel Inglesias of France's Museum of Natural History and using molecular analysis of DNA, proves once and for all that the initial classification was correct.
As a result of the overfishing, the flapper skate is on the fast track to being wiped out, the paper says.
"[Without] immediate and incisive action, the species may be in an irreversible decline towards extinction," Inglesias said in a statement.
The blue skate is in sharp decline but is still a viable species, the study says.
Iglesias said the discovery highlights the need "for a huge reassessment of population for the different Dipturus species in European waters."
The study was published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems.
Skate may be fished to extinction
Victoria Gill, BBC News 18 Nov 09;
A species of skate could become the first marine fish driven to extinction by commercial fishing, say scientists.
A study reveals that an error in the classification of the species has meant researchers have failed to see just how close to the brink it is.
The French team reports its findings in the journal Aquatic Conservation.
Marine biologist Nicholas Dulvy from Simon Fraser University in Canada says the skate is now "the most precarious marine species on Earth".
The team's genetic studies have revealed that what is referred to as the common skate is actually two clearly distinct species - the flapper skate (Dipturus intermedia) and the blue skate (Dipturus flossada).
The fish were originally categorised separately, but an influential study in 1926 recognised only one valid species - Dipturus batis . This classification has been unchallenged since.
The 80-year error has ensured that fisheries have not been catching what they thought, explained Dr Dulvy, who is also co-chair of the World Conservation Union's (IUCN) shark specialist group.
The result has been that catches of the smaller, more resilient blue skate has entirely masked the decline of the flapper skate.
Disappearing fast
The research team, led by Samuel Iglesias from the Marine Biology Station in Concarneau on the west coast of France, paints a very bleak picture for the future of the flapper skate.
Dr Iglesias and his team spent over a year working with French fisheries and taking DNA samples from the skate that was caught.
His findings finally revealed that the larger D. intermedia species was indeed in serious decline.
Dr Iglesias said: "The threat of extinction for European Dipturus together with mislabelling in fishery statistics highlight the need for a huge reassessment of population for the different Dipturus species in European waters.
"Without revision and recognition of its distinct status the world's largest skate, D. intermedia , could soon be rendered extinct."
Dr Dulvy added: "As far as we can tell, [humans have] not yet driven anything fully to extinction by over-fishing."
He and many other marine scientists are now very concerned that this skate species will be the first.