Cold-water coral reefs - WWF UK

Cold-water coral reefs
5. Current state
The sophisticated tools required to examine cold-water
coral ecosystems in their natural deep-water surroundings
are expensive and only became available to
scientists in the past decade, so information on the state of
cold-water coral reefs remains incomplete and is also
geographically biased. There is still a lot to learn about
these ecosystems, especially in areas where spot
investigations have revealed the presence of reefs and
cold-water coral associations, but where no mapping or
more detailed studies have yet been undertaken.
This chapter provides information on the current
state of cold-water coral reefs on the basis of case
examples from the Atlantic, Indian and Pacific Oceans.
Where appropriate, actions taken by national governments
to protect, manage and conserve these habitats are
referred to.
ATLANTIC OCEAN
Most of the continental shelves of the northeastern and
northwestern parts of the Atlantic Ocean provide suitable
A
B
Figure 17: (A) Map of the Norwegian Shelf showing the
trawl fields (pink) in relation to major coral occurrences
(dots). (B) A trawled coral reef near Iverryggen on the
Norwegian continental shelf at 190 m depth
Map A: Jan Helge Fosså, IMR; photo B: from Fosså et al., 2002
environmental conditions for cold-water corals to grow.
Some of the reefs found in these regions, especially on the
eastern seaboard stretching from Norway as far south as
West Africa, are among the best studied so far and have
provided most of our knowledge on the state of cold-water
coral reefs. However, even in these relatively well-known
areas of the Atlantic Ocean, new reefs are being discovered
on nearly every expedition. The largest Lophelia reef (about
100 km 2 ) was found as recently as 2002 (see below).
Norwegian Shelf, northeast Atlantic
On the Norwegian Shelf, a large number of cold-water
coral reefs have been found along the shelf break and the
edges of deep shelf-cutting troughs, including the largest
and the shallowest Lophelia reefs discovered so far: Røst
Reef, southwest of the Lofoten Islands, and Selligrunnen
Reefs in the Trondheimsfjord, respectively. There are relatively
few records from level shelf seabed. Compilations of
coral records collected from scientific cruises and fishing
reports indicate that the mid-Norwegian shelf sector
between 62°30’N and 65°30’N and the shelf break between
62°30’N and 63°50’N contain the densest occurrence of
corals, at 200 to 400 m depth (Fosså et al., 2002).
Since the mid-1980s trawling has taken place
along the continental shelf break and on the shelf
banks. The more robust rock-hopper trawls appeared at
the end of the 1980s and allow larger vessels to fish
in rougher and previously inaccessible areas. These
fisheries are targeted at Greenland halibut (Reinhardtius
hippoglossoides), redfish (mostly Sebastes marinus) and
pollock (Pollachius virens). The major trawling grounds
are indicated in Figure 17A and show the geographical
overlap with coral. In places, the outcome is the complete
destruction of a coral reef (Figure 17B).
Norway is the first country to have implemented
protection measures for cold-water corals in European
waters. Attention was drawn to the need to protect these
coral reefs after the Norwegian Institute of Marine
Research estimated that probably between 30 and 50 per
cent of the cold-water coral reefs then known or
expected to be found in Norwegian waters had been
partially or totally damaged by bottom-trawling activities
(see Chapter 4). In 1999, Norwegian fisheries authorities
established a regulation for the protection of cold-water
coral reefs against damage due to fisheries through the
Sea-water Fisheries Act and the Act related to Norway’s
exclusive economic zone (EEZ). This national regulation
prohibits intentional destruction of coral reefs and
requires precaution when fishing in the vicinity of known
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