Scuba Diver Ocean Planet Issue 06/2016 | Page 55

08 natural archway. Separated from Hirta by a narrow channel, Dùn provides Village Bay with protection from prevailing south westerlies and can be subject to some fierce tidal surges. resulting in spectacular marine life situated to take advantage of the never-ending food supply. Jewel anemones were so numerous the sight of entire cliff faces covered in every colour of the rainbow was breathtaking. The walls at the entrance were covered with incredibly dense thickets of hydroids and even the hydroids themselves provided shelter for what must have been literally millions of tiny mysid shrimps. NORTH RONA With one day left we steamed through the night, heading 210 kilometres northeast to our final survey location, North Rona. Less revered than its distant neighbour, but with a no-less fascinating history, North Rona has been sometimes inhabited for several hundred years. A small population survived during the 1600s, but were quickly wiped out after an infestation of rats ate most of the island’s produce. (It was these same rats that potentially introduced the bubonic plague to the British Isles.) Subsequently there were shepherds until the mid-1800s, after which it has remained generally uninhabited. Farmed by the folk of Lewis, nowadays North Rona is owned by Scottish Natural Heritage, who 07 An adult monkfish manage it as a Nature reserve, 08 Mixed kelp at a cave primarily for its grey seal and entrance on St. Kilda seabird colonies. The crossing was unusually calm and 17 hours later the island loomed out of a thick fog. The weather was going to worsen and we still had to get back to Orkney. Two caves were quickly identified and the first team were quickly in the water. The usual abundance of marine life clung to the entrance walls, creating the characteristic patchwork mosaics of colour. Further exploration revealed many orange and yellow sponges and mats of intricate bryozoans interspersed with hydroids and anemones. Blood-red beadlet anemones, juvenile crabs, scorpionfish and the occasional blenny all jostled for space further in. As we returned to the cave entrance, we found an unusually dense patch of plankton – tiny organisms floating just beneath the surface which had become temporarily trapped in the current. Bizarre creatures were among the plankton, including rare tiny pteropods (or sea angels) and two of post-larval monkfish. After three weeks, against the odds, we had managed to complete all the survey objectives. A little more time around the outer islands would have been welcomed but at least we got to see these fascinating and beautiful remote outposts that are part of our natural heritage. SDOP