The Offcon Project

TOPIC SHEET NUMBER 92 V2

HIGH RESOLUTION MAPPING AND NEW DISCOVERIES AT ROCKALL - THE OFFCON PROJECT

DETAILED BATHYMETRY OF ROCKALL AND HELEN’S REEF AS REVEALED BY MULTI-BEAM ECHOSOUNDER SURVEY. RED AREAS ARE SHALLOWER, DARK BLUE DEEPER AND PALE BLUE AREAS THOSE AREAS TOO SHALLOW TO SURVEY. Introduction OFFCON project

Rockall, a tiny island just 19 metres high, sits on the The OFFCON surveys have shown that Rockall supports very extremity of Scotland’s marine environment. Some stocks of haddock and monkfish and has a particular fish 180 miles due west of St. Kilda, it is buffeted year round fauna quite distinct from elsewhere in Scotland including by the extreme winds and swell that the North Atlantic rare species such as the frilled shark, a living fossil. In weather generates. As such, it is Scotland’s only truly the deeper areas of the plateau video surveys have offshore shallow water ecosystem. The islet of Rockall revealed some of the most extensive coldwater coral is actually the only part of vast plateau of submerged reefs in the north east Atlantic. Deeper still, at depths of continent that remains above sea-level. In 2011-12, 1200 m, species of bivalves and polychaete worms were as part of a research project (OFfshore Fisheries and collecting with a benthic sampling net that turned out to CONservation: OFFCON) that aims to map seafloor be new to science and are only found in association with habitats, fish distribution and fishing activities at methane seeping from the sea-floor. Rockall, two surveys on MRV Scotia were undertaken.

www.gov.scot/marinescotland blogs.gov.scot/marine-scotland/ @GreenerScotland THE ISLET OF ROCKALL FRILLED SHARK

Objective

A main objective of the surveys was to map the Between the rock and Helen’s reef is a deeper shallow reef areas around the islet of Rockall trench which is frequented by fishermen targeting using a high resolution ‘swathe’ multibeam. This squid. technology allows the seabed to be mapped to within a metre or two of spatial resolution. The data collected are being used to build a better What emerged was truly spectacular; numerous basis for the spatial management of the area for previously uncharted pinnacles, trenches, mounds, both fisheries and the conservation of vulnerable ridges and bedrock reefs were revealed. The Rock and unique marine habitats. For example in itself turns out to be a minor feature, compared 2013, data from the surveys were used by the with Helen’s reef that extends in a great sweeping International Council for the Exploration of the arc of fissures and ridges to the north-west. Sea (ICES) as a basis to protect certain areas from potentially damaging bottom-contact fishing.

ALFONSINOS (BERYX DECADACTYLIS)