Seashore Life of India

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About the Book

Covering everything from sponges to crabs, birds, and algae, Seashore Life of India introduces us to the plant and animal life along India's coastline. Descriptions of the animals are arranged in order of complexity, and include marine animals across eight phyla-Porifera, Coelenterata, Bryozoa, Annelida, Arthopoda, Mollusca, Echinodermata, and Chordata. A colour section shows these creatures in their natural habitat, and the Introduction and glossary provide interesting additional information. Young readers, as well as parents, teachers, and nature enthusiasts, will find this book informative and absorbing.

About the Author

B.F. Chhapgar, a renowned marine biologist, identified a new species of fish called Puntius sctnai. He was Curator of Taraporevala Aquarium and has worked with the Fisheries department of Maharashtra for many years.

Preface

variety oflife far unlike that on land is to be found in the sea-an aggregation of creatures, some of which are so unique that we cannot believe in their existence unless we have seen them ourselves. Observing this life is like travelling to a strange country where we need a tourist guide to help us. The function of this book is to serve as a guide to seashore life, not only to enable us to identify the more commonly occurring animals which one may chance to pick up, but also to have an idea of their peculiar habits.

Why only the seashore? The seashore is the meeting place of sea and land. And I have restricted myself to this region for three reasons. First, while sailors, fishermen, and oceanographers have ample opportunities to go to the sea, most people can see and handle the inhabitants of the sea only on the seashore. Second, the population of animals and plants is the richest in this region,

dwindling as we go farther into the sea. Third, the unique variations of temperature, saltiness, and desiccation have led to a diversity of life that cannot be matched elsewhere.

The scope of this book has perforce to be limited. In a country as vast as ours, with a coastline extending along 5600 kilometres, it is just not possible to have even an exhaustive list of all the forms of life to be found on our shores (many of which are still undiscovered). For the serious researcher, there exist numerous reports scattered in a variety of scientific journals, but most of these are inaccessible to the average student of sea life, or involve time-consuming searches through specialized libraries.

There are excellent guides to the seashore life of many countries but unfortunately in India, so far the need for such a book has somehow been overlooked. The present guide is an attempt to fill this lacuna. It has been my endeavour to present the way of life of seashore animals in a concise form, at the same time avoiding the highly technical and sometimes bombastic jargon found in 'scientific' literature. If this book succeeds in opening the eyes of young people to the mystifying beauty of life on our seashores and in whetting their appetite to know 'why' and 'how', my efforts will have been amply repaid.

Introduction

The world is full of beautiful sights and wonderful creatures, and some of the most beautiful sights and wonderful creatures occur in the sea. The seashore, or more specifically, the inter-tidal zone (that is, the zone between low and high tides, exposed at ebb tide but submerged at high tide), is the most popular of all the regions of the sea, not only because of its easy accessibility, but also because of its

great diversity of habitat and wildlife. The seashore is a linear interface between the land and the sea with its wildlife confined to a ribbon-like strip, only a few hundred metres wide.

Since it is not possible to give descriptive accounts-or even all the names-of the thousands of animals living on our shores, only common or representative animals will be discussed in this

book. Only those which can be easily seen by the naked eye are

included, so that this leaves out the exquisitely designed diatoms and protozoa, and the wheel animalcules (Rotifera).

WHEN TO COLLECT

Unlike tideless seas like the Mediterranean, the seas that lap Indian shores have tides that may range from a fraction of a metre to a prodigious 6.5 metres, as in the Gulf of Cambay. For example, the Mumbai coast has an average neap tidal range of 1.4 metres and a total average tidal range of 2.5 metres. Tides in our country are predominantly semidiurnal, that is, there are two high tides and two ebb tides in twenty-four hours. Both high and low tides occur roughly fifty minutes later each day. At the new moon and full moon, the sea water rises unusually high and recedes

unusually low; these are called the allied spring tides. During the first and last quarters of the moon, we have neap tides, when the sea water neither comes up very high nor recedes very low. Obviously, it is preferable to visit the seashore at the time of spring low tides, when the maximum portion of the shore is exposed.

WHERE TO COLLECT

The animals and plants on the seashore are not distributed haphazardly; each kind occupies a well-defined zone. "What we find on the seashore will depend not only on the state of the tide but also on the type of shore. Seashores can be roughly classified into four categories: shingle, sandy, muddy, and rocky.

Shingle or pebble beaches are covered by smoothly rounded stones. These cannot retain water between them and waves constantly roll them about so that life cannot settle on them. Shingle beaches are therefore barren and not worth collecting on.

Sandy beaches are exposed to surf (waves). These waves lift the upper layers of sand in a cloud of abrasive particles. This scouring action is harmful to life and only those forms which can take refuge by burrowing can survive. A sandy beach therefore looks apparently barren until one starts digging. We can then find typical sand-dwelling animals like the ghost crab (Ocypode), mole crab (Emerita), cockle (Cardita), razor shell (Solen), and wedge clam (Donax), among others.

Mud beaches consist of very fine particles, which can accumulate only where there is restricted wave action. The fine size of mud particles enables easy burrowing and also prevents drying up, even at the surface. Typical mud dwellers are the sea anemone (Paracondylactis), Corymorpha, tapestry clam (Paphia), and lugworm (Arenicola).

Rocky shores may be either in the form of steep cliffs running down into the sea or extensive flat slabs with many fissures and crevices. Here we may also include man-made stone or concrete structures such as marinas and wharf piles. In contrast to mud flats and sandy beaches, which can be easily burrowed, rocky shores, which are usually exposed to strong wave action can provide shelter only to animals or plants that can cling to the rock surface. Typical rock dwellers are the acorn barnacles (Balanus), periwinkle (Littorina), oysters (Ostrea), mussels (Perna), hydroids (Obelia), bryozoa (Membranipora), rock sea anemones, and seaweeds such as Ulva, Enteromorpha, Padina, and so on.

On flat rocky shores we have the limpet (Cellana), the sea hare (Aplysia), many gastropod snails, and most types of seaweeds. A large variety of life forms intolerant to desiccation like fishes, octopi, and sea slugs are found in rock pools that can retain some water even at ebb tide.

Although we have classified the seashore into shingle, sandy, muddy, and rocky, we also have mixed shores, having two or three components. Thus a sandy beach may open into mud flats at a lower level, and also have rounded stones or boulders on it. Such places provide ideal collecting sites as they have all the components of a shore.

At some places in India, for example, in the Gulf of Kachchh (Port Okha, Pirotan Island), on  Black sea cucumber India's south-eastern coast near Rameswaram,

and on the Lakshadweep Islands and the Andaman and Nicobar Islands, we have extensive coral reefs. Corals are living animals related to sea anemones that secrete an external skeleton of lime. This, after their death, serves as a hard substrate, a substitute rock, where many animals and plants live.

Marshes, occurring in patches in many of our creeks and estuaries, and in vast areas like the Sundarbans of Bengal, are typically inhabited by the mangroves- terrestrial trees which have secondarily invaded the sea very successfully.

HOW TO COLLECT

Since most of the animals and plants live attached to the surface on rock faces, they can be easily seen and picked up. However, quite a few animals lie hidden between the fronds of seaweeds. In rock pools, on sandy beaches, and on mud flats, what is visible at first glance is but a small fraction of the total population, much of which lives under stones or burrows into the ground.

Most of the animals in a rock pool can be collected by turning over stones.

While this will disturb the animals so that the active fishes and prawns will swim away to hide in cracks, and the crabs will scuttle away, you can see the slowly wriggling brittle stars and worms, or a contracting sea anemone.

Remember always to turn the stone back to its original position so that the sessile (immobile) animals such as sponges, sea anemones, tube-dwelling worms, hydroids, and bryozoa are not exposed to the sun's heat or to their enemies. Brittle stars, many worms, and some sea slugs are very sensitive to handling, and may break into pieces in your hands; gently slide them into a glass bottle or polythene bag containing sea water.

Animals on rock faces will require to be scraped off with some force. An old chisel or scalpel is ideal for the purpose. Limpets should be suddenly wrenched off while they are relaxed. Once they are disturbed and on their guard, it is very difficult to prise them off. Burrowing animals can be dug out with a shovel or a

 Hermit crab  small rake.

Conservation of wildlife in the sea is as important as on land.

Be content to watch seashore life intently. If you must collect, do not overdo it. One specimen of each kind, if required as a museum specimen, may be taken away, but no more. If you desire to study it alive, remember that most people do not have the expertise to be able to maintain marine animals alive for more than a day or two. It is best to return the animals to the seashore near the place where you collected them. It is only an inconsiderate batch of students who go rampaging about the seashore, overturning each and every stone they come across, not bothering to return it to its original position, and collecting vast numbers of each and every form of life they come across, only to throw them in the dustbin at the end of the day. Do not be one of them.

A rectangular hand-net is suitable for catching fishes, or even large crabs if you are worried about their claws nipping your fingers. Animals with sharp spines, like sea urchins, spider crabs, and lobsters should be handled with care. Blunt-tipped forceps (tongs) are ideal for lifting up delicate and soft animals like worms and sea slugs. Remember that many seashore animals are venomous or can sting. Some of the hydroid colonies and jellyfish sting badly, and the spines of fishes like the sting ray, scorpion fish, or catfish, and of some sea urchins also contain venom. Any cuts or wounds should be immediately bathed with clean water and an antiseptic applied on them.

The animals can be placed in polythene bags or glass bottles, and the larger ones, in plastic buckets. Small and delicate animals such as sea slugs are best kept in small vials. It is almost impossible to search for minute forms such as sea spiders, skeleton shrimps, amphipods, and some worms directly on the seashore. It is best to bring back a colony of hydroids, bryozoa, seaweeds, or sponges and keep them in an enamel or glass tray or jar overnight. By the next day, the lack of oxygen in the water will force these tiny animals to drop to the bottom, from where they can be picked up.

Animals can be preserved in a 4 per cent formaline solution, prepared by diluting one part of commercial formaldehyde with nine parts of sea water. Or they may be washed with tap water and preserved in 70 per cent alcohol or methylated spirit. The storage of animals with limy shells (Crustacea) for a long time in formaline dissolves the shells; they are best preserved in alcohol. Remember that formaline is very poisonous and also injurious to your eyes and skin.

Shorts are better than trousers for wading in shallow water. Many animals are most abundant at places where they are always submerged in water, even at spring low tides. A cap or hat which can be secured against the wind is essential in our climate. Shoes should be with laces; sandals and chappals have a disconcerting habit of ending up with broken straps. It is painful to walk barefoot in mud, for there are always shells with sharp edges, and near cities, even broken glass bottles. On rocks overgrown with barnacles, thick-soled shoes are a must. Hunter boots are good for shore collection as long as the treads on the soles are not worn out. Wearing smooth rubber soles involves the risk of slipping and hurting oneself The black rubberized composition on waterproof shoes meant for wear in the rainy season is ideal as the shoes grip rock firmly. (Gumboots are too heavy.) On very slippery rocks, in heavy surf, the three-point contact method of moving is the best, that is, always have either both hands and one foot, or one hand and both feet in contact with the rocks. On some shores with very flat slopes or a high tidal range, the water at high tide can come rushing in faster than you can walk. (You cannot run on uneven, slippery rocks or in soft mud.) Be careful to come out well in time before the incoming tide overtakes you. Or, while collecting on a high patch of ground surrounded by low shore level, you may suddenly find yourself surrounded by water unless you are vigilant. If collecting in the evening, it is a good idea to have an electro torch hand for use, as it may become dark while you are still at some distance from dry, even land.

Many timid animals as well as contractile animals like sea anemones and corals are best seen while submerged. When the sea bottom is exposed, they are either hidden or appear as shapeless blobs. The use of a water-glass from a boat in shallow water enables one to see under water without getting wet. You can make a water-glass by knocking off the bottom from an old bucket and replacing it with a round piece of glass to fit. You have to hold the bucket so that its bottom is below the water surface and put your head into the bucket. Of course, the use of a face mask with snorkel tube is still better, as then you can not only see sea life but also dive down in shallow water to collect it.

THE PROBLEM OF NAMES

Non-biologists are perplexed by the scientific names of plants or animals, which to them seem unnecessarily complicated or even senseless. So why have scientific nomenclature? There are many reasons for this, the main one being to avoid confusion. Many animals may have the same common or popular name. Thus the cockle ofIndia (Cardita) is a different animal from the cockle of Europe or America (Cardium). Conversely, one animal may be called by different names in different countries. Poecilia reticulata, a very popular fish called a guppy by anyone who keeps pet fish at home, is also known as peacock fish, rainbow fish, millions fish, bellied fish, and mosquito fish. If we were to use all these names, imagine the confusion of someone not familiar with the fish. They would imagine that we are talking about six different kinds of fish! Add to that the problem of languages. A prawn in Gujarat is called 'cholla', in Maharashtra, 'kolambi', and in Karnataka, 'sunkata'. Using scientific names avoids all this confusion. The system was established by Linnaeus in the eighteenth century and is now universally adopted. It is called binomial, because each animal or plant has two names- the generic (equivalent to our surname), written first and always starting with a capital letter, followed by the trivial or specific (equivalent to our personal or 'Christian' name), starting with a small letter. These names are in Latin or latinized versions of other languages. In biological classification, we have two main kingdoms-animal and plant (leaving aside the primitive microscopic forms such as bacteria and viruses). Each kingdoms divided into several phyla (singular, phylum), which are further subdivided into classes, orders, and families, among which may be interspersed subclass, suborder, and subfamily. Thus we have the following classification for a common crab:

So, in spite of Shakespeare's comment, 'What's in a name?', we follow this systematic method of naming in science. It may be noted that the name Ozius rugulosus is given to one and only one kind of crab. No other animal, let alone other crabs, will have the same name. At the same time, this crab will have this one name only, and no other name. So any person, anywhere in the world, speaking any language, when he comes across this name, can know precisely which animal is being referred to. Let us now have a look at the different animals found on the seashore. We shall start with the simplest forms-those which evolved earliest-and then go on to the more highly evolved forms.

Contents