Even after centuries of study into our planet's vast ocean ecosystem, biologists say they're still far from uncovering all its secrets -- but faced with rampant commercial fishing which threatens species lifeforms yet unknown, their's is a race against time. Over the last three decades scalloped hammerhead sharks have been fished and finned to near extinction, their numbers dropping around 95 percent across the world, though the recent discovery of a newly documented 'twin' species means this tragedy is actually two-fold.
As if the long-term outlook for scalloped hammerheads were not grim enough, researchers say that finding a look-alike species suggests that past marine censuses had likely inflated the figures of their already dwindling population. This new species, as yet unnamed, was first discovered off the coast of Nova Scotia in 2005, and was thought to be a localized variant. More recent findings of the species near Brazil, however, indicate that it is widespread and has probably been counted among scalloped hammerheads by both scientists and fishermen, says professor Mahmood Shivji, Ph.D, co-author of a study to be printed in the journal Marine Biology.
"It's a classic case of long-standing species misidentification that not only casts further uncertainty on the status of the real scalloped hammerhead but also raises concerns about the population status of this new species," Shivji tells eScienceNews.
"It's very important to officially recognize, name and learn more about this new hammerhead species and the condition of its populations through systematic surveys. Without management intervention to curtail its inadvertent killing, we run the risk that overfishing could eradicate an entire shark species before its existence is even properly acknowledged."
Researchers believe that around 7 percent of sharks counted as scalloped hammerheads are actually this new-found, similar-looking shark, pushing the endangered species closer towards the brink of extinction.
Although they are in fact two distinct species, both the new and previously documented hammerheads face the same threats from the cruel shark fin trade which claims the lives of millions of animals each year and is largely responsible for reducing their numbers to just 5 percent in the last 30 years.