Preface The expedition ARK XIX/3 with the German icebreaking RV ...

A. 4.8 Deep water coral ecology and fisheries impact in the Porcupine Seabight
and NW Porcupine Bank
Grehan, A., Unnithan, V., Wilson, M., Guinan, J., Beck, T., Foubert, A.
Wheeler, A.
A. 4.8.1 Living deep-water coral distribution patterns in the Porcupine Seabight and
NW of Porcupine Bank
Unnithan, V., Grehan, A., Guinan, J., Wilson, M., Beck, T., Foubert, A.,
Wheeler, A.
The living deep-water coral distribution observed on the dives of the "Victor 6000" in
the Porcupine Seabight and Porcupine Bank during the Polarstern ARK XIX/3a
Cruise, show a remarkable patchiness. The dives on the "Moira mounds" show that
live Lophelia and Madrepora are present in rather isolated colonies interspersed
throughout the region, with general colonisation on hard substrates such as
dropstones, concretions or dead coral fragments. The dive to the "Galway mound"
showed some of the highest concentrations of living coral observed on a mound. On
this mound both Lophelia, and Madrepora are equally abundant. This mound is
additionally characterised by a diverse fauna including glass sponges, gorgonians,
and crabs. The dives on the "Belgica mounds" were surprisingly devoid of large
patches of living Lophelia. The only exception was a small area around the Poseidon
Mound. This mound consists primarily of dead Madrepora and very isolated colonies
of both living Madrepora and some Lophelia. During this dive it was observed that the
shallower mounds appear to have less living coral coverage than the deeper ones
such as "Thérèse" or "Galway mounds". This suggests perhaps a bathymetric or
hydrodynamic control on the occurrence of living Lophelia or Madrepora.
In this short introduction to the distribution of coral, soft bodied coral such as
gorgonians, antipatharians etc have been excluded and the focus has been on
Lophelia, Madrepora, Desmophyllum and stylasterids.
The Porcupine Bank
As observed on the previous "Victor 6000" CARACOLE cruise in 2001, the distribution
of living coral in the Rockall Trough margin is very different to that observed in the
Porcupine Seabight. The Rockall Trough has perhaps a more active and dynamic
contour current system along with internal waves and tides which enhance
resuspension of sediments. The living coral distribution on the twin mound was difficult
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