Kelp Forest

Scotlands Living Landscapes

• Foreword
• Introduction
• What is kelp and where is it found?
• Why kelp forests are important in Scottish coastal waters
• Scottish kelp plants
• Light – the critical factor
• Oarweed forests
• Cuvie forests
• Kelp parks
• Beyond the kelp zone
• Kelp productivity
• Uses of Kelp
• Kelp harvesting
• Afterword

Beyond the kelp zone

In the dark, quiet areas below the kelp zone, plant domination of the sea bed gives way to animal domination. Several species of small red seaweeds and encrusting seaweeds can grow at greater depths than kelp, but even these eventually succumb to the decreasing light levels. However, the flick of a diver’s torch reveals an unsuspected world of dazzling colours and strange growth forms. Delicate, feathery hydroids and sea fans and elegant fan worms grow among large erect sponges and sea squirts which attain sizes rarely seen in shallower water. Dense colonies of the brilliantly coloured jewel anemone form bright green and red patches on vertical surfaces, interspersed with the waving arms of feather stars. Many animals which are familiar from shallower waters also live at these depths, including starfish, brittle stars, sea urchins and dead man’s fingers.

Mammals and birds

Otters are scarce throughout much of Europe, and Scotland is one of the few countries with a thriving population.

Some of the healthiest remaining Scottish otter populations inhabit the coastal areas of Orkney, Shetland, the Western Isles and the western Highlands. These animals rarely travel more than 50m off shore, and forage for food on the sea bed in 3-10m depth of water, where they catch crabs and small fish such as butterfish and sea scorpions. Although they also forage on intertidal seaweed beds, particularly in sea lochs, kelp forests are an important habitat on the open coast. The animals prefer forests with open areas or holes, where they can hunt without being hampered by the kelp.

Little is known about the use of kelp forests by sea birds, although it is believed that many species which feed in open water, such as gannets, would be discouraged by the tightly packed kelp stipes and fronds, which reduce their underwater manoeuvrability. However some seabirds, for example, black guillemots or ‘tysties’ almost certainly use gaps in the forest and the more open kelp park for hunting small fish and crabs.

Even when dead, cast kelp provides an invaluable habitat for certain waders such as turnstones and purple sandpipers, which hunt for small crustaceans and insect larvae hatched in the stinking soup of decaying weed.