The pleasures of beachcombing

The real beachcomber likes his beaches deserted, out of season, or early in the morning before the bucket and spade brigade disturb the interesting collection of sea life washed up by the tide.

The line of debris left by the tide at high water mark is known as the strand line-it is a mine of information about life in the sea and on the shore. Seaweed and shore plants mix with shells, dead starfish, cuttlefish bones, jellyfish driven in from the open sea by the current, and other fascinating remnants of marine life.

Snails, fossils, pebbles, bits of driftwood, all have a story to tell, and even the most barren-looking of beaches is actually teeming with life. Watch the sea birds swooping down to catch their prey in rock pools, or digging in the sand with their beaks, and you become aware of the variety of tiny organisms which make up the complex community of the seashore.

The waterline not only divides two elements, land and water, but also the creatures which live in them, as crossing the boundary generally means death to the interloper.

Different species thrive in various habitats. Underwater life varies with the condition of the sea-bed, which may be soft and muddy, sandy, or rock hard, and the depth; totally different communities of marine life are found at different levels. Their appearance and mode of life is dictated by their environment.

The coastline round the British Isles varies enormously — there are forbidding rocks lashed by enormous waves, steep chalk cliffs rising out of the water, wide sandy beaches, long stretches of shingle, grass-topped dunes, and mud flats.

Walk along any of these with a net and a basket and you will learn a great deal about the creatures which make their home there or have been washed up by the tide. Here is a rough guide to the kind of creatures you can expect to find along the various types of shores.

Sandy beaches
Large expanses of sand tend to look monotonous and lifeless. We see at first only the ridges left behind by the waves, but take a closer look and you become aware of the timid creatures which hide and burrow beneath the sand.

A miniature hill indicates the existence of a little beach snail; a V-shaped track shows where a worm has recently dug himself in; look closer and you will see the star-shaped traces of a beach crab. Many creatures burrow in so deeply that there is no trace at all, only the smallest of air holes in the sand for breathing.

Many sandy beaches have large areas covered with flat-bladed sea grass, anchored down by a widespread rooting system, its narrow leaves forming large matted areas which provide a home for many small creatures.

Rocky coasts
These are the richest in animal species, partly due to the presence of many varieties of seaweed which flourish on rocks and provide shelter for many forms of life.

At high tide, the seaweed is upright and whole schools of little fishes dart in and out of the strands; rapacious shrimps hunt for food, slugs and other creatures crawl along the floating leaves hunting down prey.

When the tide is out, the seaweeds hang matted and dripping from the rocks like heavy draperies, but underneath them many creatures still find shelter, mussels and limpets clinging to rocks, slugs "grazing" on the seaweed.

The little pools among the rocks are particularly fascinating. They are microcosms of the seashore and support many plants and creatures which would not survive in areas alternately exposed and covered by the sea.

If you pay repeated visits to the same rock pool, you will learn to distinguish between the permanent inhabitants of the pool and the visitors which come and go with the tide.

Many inhabitants of rocky coasts cannot move; they are anchored onto rocks, pebbles, and the larger shells of other creatures. Familiar among them are the acorn barnacles found in clusters on rocks, the tube worm, and the spiny sea urchin which digs into the sea bed and stays there.

Another form of life which cannot move of its own volition is plankton, which consists of microscopic organisms which move with the waves and currents. They provide a vital source of food for larger marine life.

Mud flats
Even the most practiced beachcomber can easily overlook the sand-shrimp — his coloring blends so well with his surroundings that he is easily camouflaged.

Crabs dig themselves in so swiftly that you need a quick eye to spot them. But it is not only hunted species which seek safety by burrowing beneath the sand. A number of hunters dig themselves in to spy on their prey and pounce at the right moment. The cuttlefish for one works his way under the sand in seconds and emerges with equal speed to catch an unsuspecting crab or fish and the ray can lie deadly still up to his eyes in sand or mud, but ready to snatch a passing victim.