Save our deep seas: stop the strip-mining of deep-sea biological diversity

IssueJune - August 2004
Feature by Karen Sack

Mars calling Earth: “what is all that blue stuff?”

If an alien spacecraft made an emergency landing on earth, then managed to repair itself and return to its home planet, it is very likely that it would report earth's environment as cold, dark, bleak and highly pressurised.

This is because, with the deep sea covering some 64% of our planet and average depths of 3,800 metres, there would be a very strong probability that our alien would have landed deep beneath the ocean's surface on the sea-floor. Now, if this same alien spacecraft managed to do some touring before returning home, it may have bumped into a beacon of light and colour in this dark environment, an undersea mountain covered with living corals and teeming with sea life.

Earth to Mars:

“It is our deep sea, below which are tens of thousands of sea-mounts and an amazing world of marine life.”

The deep ocean has its own mountains called sea-mounts. They rise at least 1,000 metres above the surrounding sea-floor but don't break the water's surface to become islands. It has been estimated that there are tens of thousands of sea-mounts across the world's oceans - with more than 30,000 believed to be in the Pacific Ocean alone.

The Earth's longest mountain range is not on land but under the sea - the Mid-Oceanic Ridge, which winds around the globe from the Arctic Ocean to the Atlantic. It is four times longer than the Andes, Rockies, and Himalayas combined.

Sea-mounts are centre-points of deep-sea marine life. Their hard surfaces are colonised by colourful forests of cold-water corals and thriving dynamic communities of small creatures. In the waters around them, live large populations of fish. There is so much marine life in these deep-sea ecosystems that scientists have called them the “old-growth rainforests of the sea”.

In such deep-sea environments, where food, light and warmth are scarce, evolution has promoted the development of large, slow-growing, late-maturing species with low rates of reproduction. Many deep-water fish live for over 30 years. Some species, like the Orange Roughy, can reach up to 150 years of age. Many of these deep-sea fish species periodically gather in huge numbers on sea-mounts to feed and spawn. It is then that they are most vulnerable to industrial-scale fishing. Whole populations can be very rapidly wiped out, and it can take several decades for them to recover.

Mars to Earth:

“But what's that huge net doing to your sea-mounts and the deep sea life?”

Currently, the biggest threat facing these deep-sea ecosystems comes from a type of industrialised fishing called bottom trawling. Bottom trawling is a fishing method in which huge nets fitted with heavy chains and steel plates are dragged across the ocean bottom, destroying everything in their path in order to catch their target fish.

In most cases, deep-water bottom trawl fishing takes place in areas where there is a very limited understanding of the biology of the species being caught, or of the ecosystems in which they live. There is the very real possibility that bottom trawling in these environments could drive such species to extinction.

The deep ocean is one of the planet's last frontiers. Only a very small fraction of the many ecosystems found on the ocean bottom (below 200 metres) have been studied. From the research that has been done though, it is clear that there are a vast number of species in these ecosystems that we know nothing about. There is also little understanding of how they function and the effects that any disturbance or damage has on the ecosystem as a whole.

Earth to Mars:

“Don't worry our politicians are going to stop all bottom trawling on our high seas.”

In February 2004, over 1000 of the world's foremost marine scientists released a strong statement (see ) calling on governments and the United Nations to establish a moratorium on high seas bottom trawling.

In their statement they say that scientists have just begun to understand the diversity, importance and vulnerability of deep-water ecosystems. Their concern is that these areas will be profoundly disturbed before scientists are able to discover what is actually down there. States at the meeting of the Convention on Biological Diversity at the beginning of this year agreed that the UN General Assembly as well as other relevant international and regional organisations must urgently take the necessary short-term, medium-term and long-term measures to eliminate/avoid those practices destructive to vulnerable deep sea ecosystems, including through the “interim prohibition of destructive practices adversely impacting the marine biological diversity associated with [these] areas....” 1

And we have our own green people who are going to make sure that we save Earth's deep-sea life.

Greenpeace and numerous other environmental NGOs agree. Deep sea bottom trawling must be immediately stopped until these deep-sea ecosystems are better understood and their biological diversity protected from this destructive fishing method.

In all 44 countries where Green peace has offices, at the United Nations in New York, and on our ships on the high seas, we are working to put a halt to deep sea bottom trawling and so save deep sea life. To find out more about this campaign and have your voice heard by decision-makers at the United Nations, visit .

Topics: Green