 |
Race against time
THE OTHER DAY I ASKED A DIVER FRIEND how many different species of plants and animals he thought might live in the world's oceans. He ran a speeded-up version of The Blue Planet through his head, made a quick tally of the coral reef fish he had seen on his recent holiday to Thailand, multiplied by ten - and came up with a figure of 10,000.
Well, multiply his figure by my age (actually, to be honest, by half my age) and you get the true figure: 230,000. That's how many marine species have been described by scientists around the world so far.
These include everything from 84 different whales, dolphins and porpoises to 6800 species of zooplankton and 15,482 marine fish.
But what really shocked my friend (and me) was that no fewer than 13,000 new marine species have been discovered in the past year alone. These range from a new clam off the coast of Chile to a miniscule mollusc discovered in vents in the Indian Ocean.
On average, two new species of marine fish are being found every week and, even in Europe, the rapid discovery of new marine species shows no end in sight.
How many more have yet to be discovered is something marine biologists spend an inordinate amount of time talking about over extravagant quantities of beer, but most agree that the final figure is bound to be several times, and perhaps even 10 times, higher.
Much of this information comes from a $1 billion research project called the Census of Marine Life (COML), which involves an international alliance of hundreds of scientists in more than 70 countries.
Effectively, the aim of the 10-year project (2000-2010) is to do a stock-take of the world's oceans, to provide better information for future conservation and fisheries policies.
It's quite a challenge, and yet already the database includes an astonishing 5.2 million records of more than 38,000 marine species.
But what it demonstrates above all else is how little we know - we're literally just skimming the surface. COML reckons that if you catch a fish below 2000 metres it is 50 times more likely to be new to science than one found at 50m.
What we desperately need is more information on the wildlife lurking in the hidden depths below the tips of our fins, as we hover at the limits of sports diving.
Unfortunately, COML's detective work is a race against the clock, because there is a good chance that many marine species are becoming extinct before we're even aware of their existence.
While COML is struggling to catalogue all known marine species, the World Conservation Union is using its veritable army of 10,000 scientists across the globe to evaluate the status of the ones we already know about. Its latest Red List of Threatened Species has just been released and it makes depressing reading. Some 15,589 wildlife species are now known to be threatened with extinction - 3000 more than four years ago.
The list includes one in eight of all birds, one in four mammals, one in three amphibians - and almost half of all turtles and tortoises.
And they're just the ones that we know about. The Red List is a gross underestimate of the total number of threatened species, because it is based on an assessment of less than 3% of the world's 1.9 million described species.
Under threat: the Napoleon wrasse |
Perhaps inevitably, one of the biggest gaps in our knowledge is marine wildlife. Very few marine species are well documented.
One of the exceptions that will be familiar to anyone who has dived in the Indian or Pacific Oceans is the humphead wrasse. Otherwise known as the Napoleon, giant or Maori wrasse, this large coral reef fish is highly sought-after at the centre of its range in south-east Asia.
Its population has halved in the past 30 years, and because virtually nothing is being done to halt the decline, it has been upgraded in the Red List from "vulnerable" to "endangered".
Although the status of most fish is poorly known, the little we do know doesn't bode well.
Eight hundred species are currently listed as threatened. But even this hides the truth when you consider that only about 6% of all 28,500 known fish species have been evaluated - and nearly half of these are in trouble.
So if I had asked my diver friend how many fish species are likely to be threatened with extinction, his answer would have been pretty close.
Now that really is frightening.
Zoologist, conservationist, writer and broadcaster Mark Carwardine writes each month in DIVER. Visit his website, www.markcarwardine.com
|
