Three 2 2 m index sites were randomly
chosen along each transect and each marked with two numbered
hard trawl floats (diameter 95 mm) attached to iron weights and
carefully positioned between the living glass sponges. Cable index
sites were laid out in a way that the cable ran through the middle of
each site. The resulting six transects and 18 index sites were surveyed
twice a year, in spring and fall, between October 2008 and
February 2012.