Loch nam Madadh (Lochmaddy Bay)
Latitude : 57° 36′n / Longitude 07° 10′w
The rich communities of plants and animals that live in Loch nam Madadh and its obs are internationally important. This is recognised by the marine Special Area of Conservation designation which, by working with local people, aims to conserve this Hebridean jewel for future generations.
A guide to the marine life and shoreline of Loch nam Madadh, courtesy of Scottish Natural Heritage. Hover over the numbers on the map for detailed points of interest.
- Map of North Uist
-  Loch nam Madadh
Loch nam Madadh – loch of the dogs – is named after the two dog-shaped rocks, Madadh Beag and Madadh Mòr, which stand guard just outside the loch’s entrance. These and a third rock to the south, known as Madadh Gruamach – the surly dog – can be seen from the ferry.
 The loch entrance
As the ferry moves into the shelter of the loch entrance, the wind dies down and surging waves drop away. Within the entrance, tidal currents sweep past the steep-sided bedrock that plunges 30-40m to the seabed. Below the sunlit tangle of brown kelp, rock surfaces are coloured by the growth of spindly sea fans, cup corals, softly branching sponges, jewel anemones, delicate filigrees of sea firs and sea mats and gelatinous masses of colonial sea squirts.
 The outer loch
Once through the deep, tide-swept entrance channel, the ferry enters the wave-sheltered outer Loch nam Madadh and passes the lighthouse island of Glas Eilean Mòr. The shallow rocky edges of the loch and islands are fringed by dense kelp forests, which become more open kelp park in deeper water. On the seabed, slender sea pens emerge from flant expanses of mud while heart urchins (“sea potatoes”) and sea cucumbers burrow under areas of gravel.
-  Lochmaddy village
The ferry docks at the crofting township of Lochmaddy. In the 16th century, the harbour was a secret rendezvous for pirates and since then it has been a bustling base for trading ships from Ireland, England and the Baltic. By the 19th century, the town had established itself as the centre of trade, communication and administration. Today, the village continues to change and grow. Recent developments reflect the increasing importance of tourism to the area.
 The centre of the loch!
The central part of the loch is a network of islands, branching inlets and wide, shallow basins. As the tide falls and rises, the inlets and basins drain and fill, and huge volumes of seawater pour over rocky sill entrances and flood through narrow tidal channels.
Navigation around this central part of the loch is extremely hazardous, particularly on the falling tide! A number of salmon farms and shellfish farms are located in the central part of the loch, as the strong tidal currents bring microscopic plankton food to farmed oysters whilst helping to keep the areas around the salmon cages clean.
 Tidal rapids and mearl beds
If you follow the guided walk from Taigh Chearsabhagh history museum and arts centre towards Sponish House, you will cross a footbridge over the entrance to Loch Houram. This is one of the best examples of turbulent tidal rapids and is a particularly good place to see otters.
Tidal currents scour the boulders and stones that litter the edges of these rocky channels; the fierce water movement encourages prolific growths of marine life. Large brown seaweeds, thongweed and kelps flex and sway in the swirling flow. At low tide, small red algae, colourful sponges and sea squirts can be seen.
In the centre of the channel, almost hidden amongst the stones, gravel and kelp holdfasts, are knobbly piles of an unusual red seaweed, maerl, known as “Scottish coral”. This calcareous seaweed grows into brittle, twiggy nodules or hedgehog-shaped lumps. The delicate tubes and feeding tentacles of fan worms project through the maerl beds, while sea cucumbers and razor shells burrow underneath.
-  Shallow basins
Tidal sills and channels link the main body of Loch nam Madadh to a number of very shallow (2-6m deep) inlets and wide basins. The soft sediments that cover the bottom are home to a variety of burrowing animals. Any patches of stone amongst the mud are colonised by large sea squirts or by large kelp, whose wide blades resemble billowing capes and are often draped with feather stars! Their stipes (stems) are covered by animal growth, including purse sponges, breadcrumb sponges and sea squirts.
-  Inner loch
The six lochs that branch off from the central part of Loch nam Madadh form the inner loch. One of these, Loch Yeor, is the most isolated. It is connected to the rest of the loch by a sequence of sills that separate the basins of Lochs Voiskinish, Blashaval and Minish. There are tidal rapids between Loch Yeor and Loch Voiskinish but between Loch Blashaval and Loch Voiskinish is an even more dramatic feature – a marine waterfall!
The sheltered waters of the inner loch, with its myriad islands and skerries, are home to otters. The seaweed covered intertidal shores and tidal rapids provide rich feeding areas, whilst the peaty banks around the loch are ideal for otters to dig out their holts.
-  Obs
In the north-west part of Loch nam Madadh, seawater and freshwater mix in the maze of obs. At low tide, water drains from the lagoons in a variety of ways: flowing over rapids, cascading down marine waterfalls, percolating through boulder and gravel barriers or via sluices and culverts. Within obs such as Loch an Dùin and Loch an Strumore, the conditions change from fully marine in the entrance basin to freshwater in the innermost basin.
Lush meadows of eelgrass and tasselweed carpet much of the soft, peaty mud that lines the lagoon basins. These seagrasses belong to the only group of flowering plants that can live in salty water, and cockles, sand gaper shells and mud snails live amongst them. In the very low salinity innermost basins, dense beds of stoneworts develop, including the rare foxtail stonewort, Lamprothamnion papulosum.