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St Kilda Today > Studying the Natural Environment > Marine Life

Marine Life

The islands of St Kilda are bathed in clear, oceanic waters and support a spectacularly diverse and stunning range of animals and plants in both the intertidal (between high and low water) and subtidal (below low water) areas.

Diver photographing marine life
Photograph: Rohan Holt

The near vertical intertidal areas around much of the islands support communities of animals and plants specially adapted to survive the frequent Atlantic storms that batter the islands. An upper broad band of white limpets and barnacles contrasts with a lower band of blue-black mussels amongst which the small red seaweed Mastocarpus stellatus grows, which in turn gives way to rock covered with pink encrusting seaweeds and the long whiplike brown dabberlocks. In a few places where there is a little shelter from the waves the nationally rare brown wracks, Fucus spiralis var nana and Fucus distichus can be found.
Beneath the surface a dense forest of kelp creates a swaying mass, providing refuge to a host of other animals and plants. The rock surface amongst the kelp holdfasts is covered by a variety of different sponges and sea anemones.

Going deeper with decreasing light levels, the kelp forest thins into a park but remarkably some kelp plants survive to depths in excess of 45m compared to a maximum of 25m on the west coast mainland of Scotland and only 10-12m on the east coast.

Kelp forest with sea urchin (Echinus esculentus)
Photograph: Sue Scott

Space is at a premium, every square centimetre of rock is covered in a kaleidoscope of form and colour. Carpets of jewel anemones ranging from greens and pinks to vivid reds, startling bunches of orange deadman's fingers (soft coral), great swathes of orange, yellow, grey or green sponges, delicate hydroid and bryozoans all flourish in the plankton rich waters. Mobile animals such as chitons, snails, sea slugs, crabs and various starfish including featherstars, sun stars and cushion stars are to be found.


A kaleidoscope of form and colour covering the rocks
Photograph: Sue Scott

Sea slug (Polycera sp.)
Photograph: Rohan Holt

Starfish Asterias rubens and anemones Sagartia elegans
Photograph: Sue Scott

In the almost azure blue surface waters fish abound, shoals of herring create a dazzling light show as the sunlight reflects off their slender, silver bodies. Seals and even larger predators such as basking sharks and minke whales patrol these rich inshore waters. The marine life around St Kilda is a wonderful resource and a gem in the crown that is Scotland's spectacular natural heritage.

Further Information

Scottish Natural Heritage
2/5 Anderson Place
Tel: 0044 (0) 131 554 9797
Fax: 0044 (0) 131 554 7900

© The National Trust for Scotland