Marine survey of Britain’s remotest nature reserve to reveal undersea wildlife

July 2008. The undersea world surrounding Scotland's most remote National Nature Reserve (NNR) is to be explored and charted for the first time next week in a marine survey being conducted by Scottish Natural Heritage (SNH).

North Rona, best known for huge seabird colonies, is one of Scotland's most remote and isolated island outposts, sitting forty seven miles out in the Atlantic north east of the Butt of Lewis. Despite its NNR designation the marine environment of the island has never been fully surveyed and this year SNH has launched a two stage survey project to map and record the marine life which exists in the seas around the island.

Reefs, caves and gullies
Now SNH hopes to add to what we know about the reserve by going beneath the waves to explore North Rona's reefs, caves and gullies. Heading up the SNH team is Dylan Todd who is coordinating an initial eight day sweep of the sea around North Rona aboard the specially chartered Orkney survey craft Ocean Explorer.

He said: "We'll be gathering a huge amount of information on the rich and diverse marine life surrounding North Rona in order to develop a management plan to help protect the area. We expect to find kelp forests extending as deep as 35m and areas of open rock supporting rich marine communities of sponges, anemones, soft corals and ascidians. We'll also be exploring sea caves used by grey seals for shelter and passing this information to our colleagues at the Sea Mammal Research Unit in St. Andrews as well as collecting rock samples for the British Geological Survey to conduct geological analysis."

Uninhabited
Now uninhabited, North Rona has strong links to the neighbouring 'mainland' of Lewis where historically people from Ness travelled seasonally to fish its waters and graze sheep on the lush grassy slopes. Indeed physical evidence and the Gaelic place names of the landscape reveal that despite its remoteness, the island has been home to a succession of inhabitants down through the centuries.

Britain's least visited Nature Reserve
In more recent times interest in the study of the island's natural heritage was sparked by the visit of the distinguished Scottish naturalist Frank Fraser Darling who spent a year on North Rona in 1938 studying the grey seal colonies.

Now owned and managed by SNH, North Rona is Britain's least visited National Nature Reserve, designated for its important breeding habitats for grey seal and seabird colonies, especially European Storm-petrel and the larger Leech's Storm-petrel.

Sea floor map
The first stage of the survey will build up a detailed map of the sea floor around the island using a high resolution side-scan sonar to accurately map the seabed. Over the eight days the Ocean Explorer will crisscross the marine Special Area of Conservation collecting bathymetric data to determine the seabed topography including the reefs and well developed sea caves.

The team will spend time on the island itself which has a small hut maintained by the Sea Mammal Research Unit for the occasional research teams and visitors to the island to use.

The North Rona broad scale marine survey continues SNH's recent work in charting the rich and diverse natural heritage of Scotland's seas which include surveys of St Kilda, Loch Madaidh in Uist, Moray Firth and Loch Creran in Argyll. The next stage of the North Rona survey will be the full undersea survey of the archipelago using a remotely operated vehicle (ROV) to explore the nature and wildlife which abounds on the reefs beneath the waves. Dylan says he and his colleagues are particularly looking forward to this stage of the survey

"The cold sub-arctic waters around North Rona results in a characteristic boreal northern latitude community with the influence of the North Atlantic Drift apparent in the presence of many southern species. This rich marine life coupled with the large breeding group of grey seals, the third largest in the British Isles, makes this survey particularly exciting for me, it's what fieldwork is all about."