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Surveys support conservation of Scotland’s unique marine habitat

By Robert Myles     Dec 22, 2013 in Environment
Tobermory - Monitoring of cetaceans — whale, dolphin and porpoise species — in 2013 by the Hebridean Whale and Dolphin Trust (HWDT), off Scotland’s west coast, has identified an impressive variety of these large marine mammals.
A registered charity, established in 1994, HWDT, based at Tobermory, on the island of Mull, focuses on pioneering practical, locally based education and monitoring programs on cetaceans in the Hebrides.
The 2013 research, part of the HWDT’s unique and long-term monitoring project of cetaceans, underscores the biodiversity of one of the world’s most precious marine habitats in the seas around the necklace of islands, known as the Inner and Outer Hebrides, that pepper Scotland’s Atlantic seaboard.
The seas around Scotland’s Hebridean islands are one of Europe’s most important cetacean habitats. The fragmented coastline, a mix of large and small islands with fjord-like sea lochs indenting Scotland’s mainland coast, combined with strong ocean currents, provide a wide variety of habitats making the Hebrides one of the most biologically productive areas in the UK. To date, 24 cetacean species have been recorded in the region. Many species noted off Scotland’s west coast are national and international conservation priority species.
Marine wildlife and the ecosystems on which they depend face continuing threats from a range of human activities. On the larger scale, climate change has the potential to disrupt cetacean migratory patterns and the habitats of species resident in Scottish waters. More local threats include entanglement in fishing gear, pollution and underwater noise. HWDT are determined to maintain their pioneering research to ensure that cetaceans in Scottish waters survive and thrive. To that end, the charity is actively seeking volunteers to help continue their marine surveys in 2014.
During 2013, HWDT documented 400+ encounters with cetaceans and basking sharks — the second largest fish found in the oceans. On average, adult basking sharks weigh in at just over 5 tonnes and are between 6 and 8 meters (20 to 26 feet) long. Some larger specimens have measured over 12 meters (about 40 feet) in length.
In addition to recorded encounters with large marine animals, HWDT made almost 1,000 underwater detections of cetaceans using specialist listening devices.
Aided by 48 volunteers working beside marine scientists on board HWDT’s research yacht, Silurian, HWDT carried out nine surveys in 2013. In the process, the Silurian clocked up more than 3,000 nautical miles covering most of the Hebrides as well as venturing as far as remote Cape Wrath, in the very north of the Scottish mainland, to Ballycastle, across the North Channel, in Northern Ireland in the South.
The Silurian’s mission highlights included a rare sighting of three members of a school of killer whales in August near the Isle of Skye. This particular school of killer whales, believed to be the UK’s only resident group, has been dubbed the ‘West Coast Community.’ The small group comprises just five males and four females. Sadly, no calves have been spotted, meaning there’s every chance the West Coast Community will become extinct in our lifetime.
During 2013, other highlights from HWDT surveys included:
• 417 encounters with cetaceans and basking sharks, comprising: 321 encounters of harbour porpoise; 34 of minke whale; 32 of basking shark; 22 of common dolphin; six of white-beaked dolphin; one of killer whale; and one of Risso’s dolphin.
• Recorded acoustic detections of 821 harbour porpoise; 129 common dolphin; six white-beaked dolphin; and one Risso’s dolphin.
• Visual sightings of 316 harbour porpoises, with the species being detected acoustically 821 times. Scotland’s west coast is one of Europe’s most important habitats for harbour porpoises.
• 50 basking sharks recorded in nine days alone in June. Sightings of basking sharks in the waters off the Hebrides have been increasing in recent years.
The recording of the Risso’s dolphin was of particular note. Relatively common off the US Pacific seaboard, and although its habitat includes north-west Europe and the Mediterranean, Risso’s dolphin is a rarity in Scottish waters. The 2013 HWDT detection helped add to the sparse acoustic data currently available for this species.
Commenting on the 2013 surveys, Kerry Froud, HWDT’s Biodiversity Officer, said: “The impressive range of species of cetaceans and basking sharks that we have documented this year highlights the wealth of marine life in Scotland’s west coast ocean environment – and the importance of ensuring the continued survival of these spectacular animals and maintaining the healthy seas that support them.”
Over the years HWDT has built the most comprehensive database on the presence and movements of cetaceans along Scotland’s western shores. Such is the wealth of data on cetaceans assembled by HWDT that it’s become instrumental in arguing the case for giving legal protection for conservation measures in the shape of statutory Marine Protected Areas.
HWDT’s researches have contributed to a proposal for constituting a network of 33 marine reserves. A decision is due to be made by the Scottish Government on giving Marine Protected Areas statutory clout in spring 2014. Such a move would provide additional protections to Scotland’s marine environment by preventing damaging activities within the reserves.
Looking at the wider picture, HWDT’s data will also contribute to the Joint Cetacean Protocol, a government-backed, UK-wide initiative that combines widely sourced data, adding to the knowledge-base of cetacean distribution and trends.
For 2014, HWDT is recruiting volunteers for its upcoming surveys along Scotland’s west coast on board its Silurian research yacht. Each volunteer’s tour of duty lasts almost two weeks. Those participating have the opportunity to work alongside marine scientists, collecting data from visual surveys, as well as conducting acoustic monitoring using a variety of onboard instruments, including hydrophones.
Full training is provided but volunteers are expected to be ‘part of the crew’ and assist with the day-to-day running of the research vessel — as the HWDT point out on their website, volunteers take part in a scientific marine survey and not a whale watching experience!
Places for the 2014 HWDT surveys, which depart either from Tobermory on the Isle of Mull or Kyle of Lochalsh in north-west Scotland, are available from May to September. Participation costs range from £800 to £1,300, which covers boat expenses, supports HWDT’s research programme and includes accommodation, food and insurance onboard Silurian. Further information on volunteer participation can be found on the HWDT website.
More about Hebridean Whale and Dolphin Trust, HWDT, HWDT Scotland, Hebridean Islands, basking shark
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