Men have died for the living jewels of the ocean

This edited article about ocean life originally appeared in Look and Learn issue number 454 published on 26 September 1970.

Diver with Coral reef and angel fish by E S Hodgson

No jeweller’s shop window can compete in variety and depth of colour with the creatures that live beneath the sea. Some of these creatures actually supply the jewels and adornments that are found in jeweller’s shops.

Perhaps the most famous is the pearl oyster.

This small mollusc makes inside its shell the beautiful pearls which have adorned womankind for many centuries.

But why does it do this?

The answer is simple. It does it because it has an irritation and wants to get rid of it.

If a grain of sand or some other small article gets inside the shell of a pearl oyster, the oyster covers it with layer upon layer of a substance known as nacre, or mother of pearl. It stops only when the irritation has stopped and, by that time, the pearl may be of quite considerable size. It may also be a number of different colours – creamy-white, pink, or in very rare cases, black.

Pearl oysters are found attached to rocks by divers at depths of between 50 and 150 ft. Perhaps the best pearl divers in the world are Japanese women, for some of whom collecting pearls is a unique way of life.

Coral, of course, is also used to make jewellery and although this is not a living thing, it is made by living things. It is made, in fact, by tiny organisms known as coral polyps.

Coral reefs are the homes of these tiny creatures and they are also the homes of numerous colourful and unusual fish.

Among these coral-dwelling fish are butterfly fish. These have tiny mouths which are situated at the end of snouts like tubes and, because of their unusual shapes, are ideally suited for poking into tiny crevices in the reefs to find food. They have very bright colours and unusual markings as a rule and these, rather surprisingly, supply the fishes with a very effective camouflage since they break up their outlines.

Chinese fish were first found only a short while ago, and these, which live in the New Caledonia reef, have the peculiarity of swimming in an almost upright position.

Another rather strange fish is the Striped Goby. These creatures swim on the bottom of the sea where they scoop up sand in their jaws and carry it to where they want to make their nests.

The Moorish Idol is also a very highly-coloured and exotic reef-fish. But, since it lives among very bright coral, its own colours give it a very effective disguise.

Other strange fish which have the effect of living jewels are Siganids or rabbit-fishes. These are mainly vegetarian and are provided with just a single row of teeth in their very small, rabbit-like mouths.

Pipefishes are not so colourful. There are various kinds, however, and they are certainly unusual, since they look like swimming pipe-cleaners. They are closely related to sea horses and the females lay their eggs in the brood pouches of the males.

Clingfishes are rather weak swimmers, but manage to protect themselves from being swept away in strong currents or heavy seas by sucker pads on their pectoral fins.

No doubt certain molluscs, particularly oysters, would be happier if the Cliona or shell-boring sponges were swept away. These sponges often cause a great deal of damage to the shells of molluscs.

Some sponges are really beautiful. The Carpenter’s Glass Sponge has a most delicate formation and is generally found at considerable depths.

The Crumb-of-bread Sponge, too, is an attractive creamy white colour. In actual fact, its surface is covered with circular craters which lead into numerous canals, running like passages through the sponge itself.

Not surprisingly, more and more people are visiting these wonderlands beneath the waves. If travel firms are wise they will soon be advertising trips beneath the surface.