Life on the Bottom...
Life on the seabed depends on its composition, on depth, current, and exposure to waves. In the Narrows colourful sponges, some more than a metre across, with soft corals, hydroids and sea-anemones occur. These filter plankton from the water sweeping over them.
Coarse gravels and sands are home to sea-cucumbers and dog cockles, largely buried for protection, and tough sea-mats, able to withstand the scouring of water-borne sand.
Burrowing purple heart-urchins are found in the gravels off Ballyquintin Point. marine life
Rocky shallows support forests of swaying kelp - home to wrasse and butterfish with tortoiseshell, blue-rayed and keyhole limpets, sea-slugs, sea-urchins, starfish, lobsters and crabs among the understorey of red seaweeds.
In sandy gravels there are sand-eels, razor-shells, various species of sea-snail, lugworms, sea-potatoes (a burrowing urchin), sea-cucumbers, burrowing brittle-stars, burrowing sea-anemones and sea-pens. King scallops, starfish,brittle-stars, burrowing sea-anemones, sea-squirts and crabs are found where the bed comprises muddy gravels.
Where the currents are gentle and there is no turbulence from waves there may be beds of horse mussels on an otherwise muddy bed - a community described as mud with shell.
Up to one hundred other species of animal can be associated with the horse mussels, many depending on them for a hard surface above the mud to which they can cling.
Towards the south of the Lough brittle-stars predominate on the mussel beds. Further north they support a multitude of sponges, hydroids, sea-anemones, sea-mats, sea-squirts, starfish, feather-stars, sea-cucumbers, sea-urchins, sea-slugs, sea-snails, scale-worms, tube-worms, crabs, squat lobsters and small scallops.
In muddy areas where the horse mussels are absent there are only a few species. The most obvious are Dublin Bay prawns, Fries' goby (a fish which shares the prawns' burrows) and sea-mice (large scale-worms).
