Natural England - Spotlight on the Isles of Scilly

Spotlight on the Isles of Scilly

22 October 2012

Two reports published this week focus on the Isles of Scilly: one which monitored grey seals during their pupping season; and one which monitored the condition of reefs in this internationally important European Marine Site.

Small group of grey seals
Small group of grey seals of different age and sex classes (seal mother and pup - middle left)

A third report monitoring the offshore reefs surrounding the Isles of Scilly will be published by Natural England soon, in partnership with CEFAS (Centre for Environment, Fisheries and Aquaculture Science). This pioneering survey work has used acoustic methods to outline the underwater topography and the extent of the reef. Drop-down cameras filmed videos of the reef at depths of up to 90 metres, revealing large colonies of Ross corals in good condition.  In addition, the new data has revealed massive sandbanks to the north-west and south-east of the islands, hitherto unchartered and unnamed; and so will be referred to in this forthcoming report as the East Bank and West Bank.

Watch video of our marine scientists conducting their survey work underwater in the seas surrounding the Isles of Scilly in 2011external link.

Natural England’s marine scientists are responsible for monitoring marine wildlife populations and for assessing the condition of undersea habitats and features within designated marine protected areas in England’s inshore seas. We provide advice to relevant authorities regarding the protection and enhancement of marine wildlife and habitats; and our survey work is published in the form of detailed reports – available online to everyone.

Marine environment survey work often involves collaboration and sharing resources with other organisations, because it is more costly than gathering evidence on land. Sangeeta McNair, the senior marine adviser who managed these research projects, said: “We had invaluable support from local boat owners who know these waters like the back of their hands. They took us to the best places to dive for the kind of habitat we wanted to survey, and to remote rocky islands where grey seals rest and breed.”

She continued: “Our team consisted of experienced divers, qualified to carry out the research themselves, which is more economical than contracting external divers. And we also kept costs down by borrowing a Rigid Inflatable Boat from the Isles of Scilly Inshore Fisheries and Conservation Authority.” Being able to dive to the required standard is a key skill for Natural England’s marine staff.

Grey seals (Halichoerus grypus) are the UK’s largest land-breeding mammal.  Adult males can weigh over 300kg while the females weigh around 150-200kg.  The coat colour varies from grey to brown to silver, often with blotches, and the breeding season in the Isles of Scilly runs between August and December. Natural England’s report showed that the Isles of Scilly remain an important breeding site for grey seals, with white-coated pups observed during all five phases of survey work. Grey seal pups have a white coat when born, which they moult around the time of weaning. The pups then remain on the breeding colony for up to two weeks before going to sea without any more parental care.

A second report monitored the condition of reefs in Isles of Scilly Special Area of Conservation (SAC), which was designated as such in 2000 because of its important reefs, subtidal sandbanks, intertidal mudflats and sandflats, and the grey seals. It hosts particularly fine examples of seaweeds found in kelp forest communities. There are vertical rock faces which support jewel anemones, yellow staghorn sponges, dead man’s fingers and sunset cup corals. And its subtidal rock and boulder communities are covered by encrusting animals such as anemones, hydroids and pink seafans.

The Isles of Scilly lie 28 miles (45 km) off the tip of Cornwall, making them the most south-westerly part of Britain. The Isles consist of over 200 low-lying granite islands and rocks, representing England’s only oceanic archipelago.