Norway scores top marks for conserving cold corals

Posted: 26 June 2009

Author: Don Hinrichsen

In the run up to this week's meeting of the International Whaling Commission in Madeira, Norway was heavily criticised for its subsidized whaling industry, but Norway gets full marks from conservationists as one of the few countries to protect its deep cold water corals from overexploitation. Here Don Hinrichsen explains why this is so important in the battle to save ocean species..

Most people associate coral with the world's extensive tropical reefs, teaming with a host of colourful fish, shellfish, invertebrates and marine mammals. But coral communities, in fact, are found in all of the worlds' seas, including 1000 meters deep in the near freezing waters of the Antarctic, where water temperatures average around +4 C.

Coral reefs are the marine equivalent of tropical rainforests - home to thousands of species of plants and animals and essential feeding and breeding habitats for many commercially valuable species of fish and shellfish. Cold water reefs contain upwards of 750 species of fish and shellfish and provide nursery grounds for commercial species, such as redfish.

Tropical and sub-tropical coral reefs cover some 600,000 square kilometres of ocean. Yet up to 70 per cent could be lost within 40 years. The fate of most of the world's deeper cold water corals is not known. Very few of these deeper, more inaccessible, coral reefs have been studied and mapped.

White coral polyps, Norway
White coral polyps, Norway
Glass coral polyps (Lophelia), Norway. Photo credit: PÃ¥l Buhl-Mortensen, IMR
Coral reefs, both warm and cold water varieties, provide one quarter of the habitat for all marine fish species and are by far the largest living structures on earth, dating back 8,000 to 10,000 years. They also grow very slowly. Cold water corals such as the Lophelia corals found in Norway's coastal waters, grow at a snail's pace, averaging just 4-25 millimetres a year. Some of the biggest reefs are more than 9500 years old, having been formed just after the last ice age. But they are incredibly fragile. Once damaged, Lophelia can take hundreds of years to regain their critical ecological functions.

Unlike tropical and sub-tropical corals reefs which grow in relatively shallow waters, deep sea corals do not obtain energy directly from sunlight. Instead they capture microscopic animals and plant matter that drift past in the water column. Because of this, their polyps - the animals which build coral colonies - tend to be much bigger than tropical corals; some are the size of cauliflowers.

Cold water coral reefs often are found where the currents run fast; on the continental shelf breaks, ridges and even in deeper areas where they colonize mounds and ridges. Not all deep water corals even build reefs. Many grow in thickets and lush gardens.

Norway leads

Norway is unique in that it has not only studied cold water coral communities, it has given protection to a number of them. According to PÃ¥l Buhl Mortensen, Senior Scientist at the Institute of Marine Research in Bergen, there are probably around 7,000 cold water reefs in Norwegian territorial waters, "but we have identified and mapped only 600 of them," explains Mortensen. "Norway has the highest density of cold water reefs in the world."

Conservation has come just in time, according to conservationists with the World Wildlife Fund and Greenpeace. Somewhere between 30 and 50 per cent of Norway's deep water coral reefs had already been damaged or destroyed before protection measures could be taken. Most were victims of rampant bottom trawling as well as oil and gas exploration.

Bottom trawling is the bane of coral, both tropical and cold water species. David Griffith, General Secretary of the scientific advisory board for the International Council for the Exploration of the Sea, likens towing a heavy trawl net through cold water coral to "driving a bulldozer through a nature reserve. The only practical way of protecting these reefs is to find out where they are and then prevent the boats from trawling over them."

The invention of rock-hopping gear has rendered every area of the ocean bottom vulnerable to the destructive might of these heavy trawls. The largest, which sport heavy rollers over 30 inches in diameter, are very powerful, and can move boulders weighing 25 tons.

"Rock-hopper gear smashes reefs and other vulnerable habitats and species," says Dr. Jan Helge Fosså, a coral specialist working at Norway's Institute of Marine Research in Bergen. "Bottom trawling is the worst threat against biodiversity in the deep sea."

In an experiment off the coast of Alaska, over 50 per cent of cold water corals damaged by trawling had not recovered a year later. Huge scars of up to four kilometres long have been found on the ocean floor in the Northeast Atlantic, as if a huge bulldozer had flattened everything in its path. Corals destroyed this way or affected by pollution and oil and gas drilling can take hundreds of years to recover.

Ecosystem functions

Conserving these deep cold water corals is the only way to preserve them and maintain the valuable ecosystem functions they serve. Besides promoting reef biodiversity, setting aside no-trawl zones and preventing oil and gas exploration also helps to replenish collapsing fish stocks. Norwegian fishermen have endorsed their country's conservation efforts because they recognize the importance of deep water corals for their own livelihoods.

Dead lophelia coral
Dead lophelia coral
Octocoral and anemones on dead lophelia coral. Photo © MAREANO/IMR
A study carried out by WWF-Netherlands and the International Coral Reef Action Network (ICRAN) estimated that coral reefs provide around $30 billion in goods and services each year. The most well know socio-economic connection is the fishing industry, which hauled in $85 billion in seafood in 2004, providing direct employment to over 40 million people. Coral reef-based fishing is estimated to have contributed nearly $6 billion of this amount (see table below).

Potential Economic Value of the World's Coral Reefs per year (in billions of US dollars)

Goods/Services Amount

Fisheries $5.7Coastal protection$9Tourism/recreation$9.6Biodiversity value$5.5Total $29.8Net Present Value (over 50 years) $797.4

Source: The Economics of Worldwide Coral Reef Degradation, WWF-Netherlands/ICRAN, 2003.

As of 2009, Norway has actively protected five deep water coral areas - rich in species diversity - from any kind of exploitation. These include:

  • Røst Reef. The world's largest known Lophelia reef is 45 kilometres long and three kilometres wide and has been under protection since 2003. It is found in Norway's northern coastal waters around the Lofoten Islands.
  • Sula Reef. This cold water reef is 13 kilometres long and up to 400 metres wide. It consists of some 500 individual mounds, a number of which reach as high as 35 metres. It is situated along the west central Norwegian coast.

  • Ever Ridge. This reef found off Norway's west coast, near Bergen, was damaged by bottom trawling before set aside as a protected area.

  • Tautra Ridge. This is the world's shallowest Lophelia reef, lying in 40 meters of water on the west coast.

  • Tisler Reef. This cold water reef, discovered in 2002, is two kilometres long and ranges in depth from 74 to 155 metres (240-500 feet). It lies in the Skagerrak, between Norway and Sweden and is the only reef known for pale red Lophelia corals in this particular body of water, providing an important habitat for sea fans, sponges, worms, starfish and crustaceans.

Lophelia come mainly in two colours - various shades of red and alabaster. Though the number of species of deep water coral do not compare to their tropical counterparts - Australia's Great Barrier Reef has 350 species of hard and soft corals -- the habitat diversity that they provide is still impressive.

Pooling research

Norwegian marine scientists have documented more than 700 species of fish, shellfish and invertebrates associated with deep cold water coral communities. "Since the diversity of animals found together with deep water corals is high," points out Mortensen, "we've probably identified only a fraction of the actual number of marine species found in these unique ecosystems."

Cold water reefs do not have as many symbiotic organisms as found on tropical reefs. However, one curious relationship has been extensively documented. The polychaete (marine worm) with the Latin name, Eunice norvegica, has both a symbiotic and parasitic relationship to Lophelia corals. This polychaete regularly steals food from Lophelia, but in return removes sediment particles from the polyps, reducing their susceptibility to be colonized by sessile invertebrates (such as sponges or bivalves) or infected by disease microbes.

Several major research initiatives have been launched in recent years to study cold water corals. One in particular, the TRACES project - Trans Atlantic Coral Ecosystem Study - will investigate cold water coral communities found along the continental shelf and slope, and also in deep water canyons and on seamounts, in the North Atlantic. Norway's scientific partner for this trans-Atlantic scientific program is the Institute of Marine Research.

"Pooling scientific expertise makes sense and will help advance our understanding of these complex cold water communities," says Mortensen.

The Institute is also overseeing the construction of a deep water seabed observatory in waters off Norway's north coast. Funded by the petroleum production company, StatoilHydro, it will be functional by the end of 2009. The observatory will monitor biological activities in the reef and record natural changes in the reef environment. Remote monitoring equipment will consist of underwater cameras, echo sounders and various sensors to record changes in reef ecology.

"Norway wants to see the destruction of cold water coral reefs ended," insists Norway's former Environment Minister, Mr. Borge Brende. "We have taken the first steps to stop the destruction of our own reefs, and more will follow. But other nations have to increase their activities to protect their reefs."

Norway's marine scientists are in agreement. "Cold water corals are not only extraordinarily beautiful, but also important for the biodiversity of the deep sea," points out Dr. Jan Helge Fosså. "There is still so much to discover about them. Damaging bottom trawling must be stopped in areas where these corals live - if we destroy the reefs, it takes centuries for them to recover."

Don Hinrichsen is a Controbuting Editor of this website and author of Coastal Waters of the World, Island Press, Washington DC, $60 hb.