The Four Idols

 

LOPHELIA PERLUSA  (A cold-water coral) 

                                                        Lophelia Perlusa

Cold water coral grows in deep water seas especially, but not exclusively, in the North East Atlantic, at depths from 150ft to more than 10,000ft where sunlight is dim to non existent and water temperature gets to below 4’C.  These reefs, mainly made up of the species Lophelia Perlusa, provide sanctuaries and breeding grounds for a great diversity  of bottom dwelling marine species.                                                                                    First discovered more than 250 years ago, it was not until modern times with the invention of manned mini-submarines that scientists began to understand these organisms.  Pioneering work by J B Wilson (1979) shed light on a coral colony on the Porcupine Bank off Western Ireland.  Dr Anthony Grehan of the University of Galway described the area as “the most pristine thriving example of cold water coral that I’ve encountered in 10 years of study in Irish waters.”  The reef area is marked on 15th and 16th century maps as Hy-Brasil, sometimes referred to as Atlantis.

Further North the Darwin Mounds were discovered in 1998, during survey work for the oil industry  The mounds are about 1000 metres deep 190 km NW off Cape Wrath.  The large field of sand mounds covers about 100 square kilometres each mound being circular, up to 5 metres high and 100 metres wide.  The mounds are surmounted by living stands of Lophelia Perlusa, this is unusual in that the coral appears to be growing on sand rather than a hard ground   At the WWF’s Ocean Recovery Summit in October 2001 the UK government made a commitment to protect the Darwin Mounds,  deep-water bottom trawling with nets as heavy as 1 tonne had been taking place.  Researchers from the University of Glasgow found pieces of coral at least 4,500 years old in nets of trawlers operating off the coast of Ireland and Scotland.  Pieces of coral up to a 1 square metre (11sq ft) were found in nets of French trawlers   that had been scraping the seabed, not only the coral but mounds themselves had been destroyed.   In 2004 the EU gave permanent protection to the unique coral reefs off the UK and Ireland, since then deep-water trawling in the area has been made illegal.

The largest North Atlantic cold-water coral reef is the Rost reef, discovered in 2002 in the Lofoten Archipelago in Norway, it is approximately 35 x  3 kilometres.  The Sula reef West of Trondheim is 13 kilometres by 700 metres and is up to 700 metres high.  Also discovered and mapped in 2002 is Norway’s Tisler reef which lies in the Skagerrak between Norway and Sweden.  It is estimated to be 8600 to 8700 years old and contains the only known yellow Lophelia Perlusa.  The species being generally creamy white or pink.

Lophelia Perlusa can form reefs or reef fields with or without bioherms (build up of organic matter under the reef structure) but can also occur as isolated colonies.  Large reefs can be thousands of years old.   Any damage to these ancient coral skeletons will have a  grave impact on this eco system which is home to clams, shrimps, sponges, lobsters, bivalves and a plethora of bottom living invertebrates and fish such as red fish, ling, tusk and pollack.  Those reefs that are in good condition can be breath taking examples of pristine habitat, mirroring the description in pioneering studies of the reefs off SW Ireland.  All the evidence for reduction in reef condition over the past decade shows that fishing is the major cause based on catch records, in situ video and acoustic images of trawl tracks through reefs.  Information collected by surveys and fishermen’s interviews suggests that between one third and a half of the total reef area off Norway has been damaged to an observable extent.  Surveys off Ireland and the UK show that the largest reefs have suffered less, as trawlermen try to avoid these regions due to potential damage to their gear.