After centuries of science and exploration, you might think we know just about all there is to know about the planet we inhabit.
But in the last year alone, scientists have discovered 1,451 new species in our oceans, according to an international audit of the seas published today.
The marine creatures include weird and wonderful beasts from the deepest, darkest oceans, microscopic shrimp from coastal caves and even two new types of dolphin.
Marine explorers off the coast of Australia discovered the venomous ‘Keesingia gigas’ jellyfish last summer – long as a man’s arm and powerful enough to kill a human.
The ‘star-gazer’ shrimp was found in the seas off South Africa, with striped eyes fixed on top of its tiny red body, seemingly staring at the heavens. And in 2014 biologists identified two new species of dolphin – one found near Papua New Guinea and the other in a Brazilian river – both of which are already threatened by fishermen.
Despite the expansion of our knowledge however, scientists estimate we still only know about a tenth of the marine life on Earth.
The World Register of Marine Species – which aims to become an inventory of all known ocean life – numbers 228,000 species, with new names being added every day.
But scientists estimate there could eventually be two million on the list as our knowledge of the oceans grows.
Over the last eight years since the project started, scientists have pored over records, examined historic journals, and poked and prodded the bodies of mysterious creatures of the deep.
After countless hours of research, they have found we know only a fraction of the fish, whales and sharks swimming around our shores, or the squid and shrimp found in the darkest reaches of our oceans.
The acceleration in research means four species are being added to the record a day.
Over the last eight years 122 sharks and rays have been added to the register, along with 131 members of the goby fish family and hundreds of different sponges.
But experts say we still know little about the waters that make up 70 per cent of the Earth’s surface.
At the current rate, it would take 360 more years to identify every creature thought to exist in the oceans, the researchers say.
Dr Jan Mees, of the Flanders Marine Institute in Belgium and co-chairman of the marine register programme, said: ‘It is humbling to realise that humankind has encountered and described only a fraction of our oceanic kin, perhaps as little as 11 per cent.
‘The main gap at the moment is because of the under-exploration of the oceans.
‘There are many, many places we have never been.’
But he added: ‘Sadly, we fear, many species will almost certainly disappear due to changing maritime conditions – especially warming, pollution and acidification – before we’ve had a chance to meet.’
‘The knowledge is vital for conservation efforts.
‘Without knowing what species are there, we have no way of knowing what is at risk.’
Some discoveries have significant benefits.
Certain varieties of sea sponges, for example, have yielded valuable cancer-fighting agents.
Experts estimate marine life has the potential to create more than 200 potential cancer drugs.