R. Cadwallader Smith

Fish Families

BABY fish, like baby frogs, when they first see the world are quite unlike their parents. The sea swarms with countless numbers of these fish-babies: if you scooped up some of them in a bucket, you would hardly know that they were fish. But let us begin at the beginning—the egg!

A bird's egg, as we all know, is a hard shell containing "white" and yolk. Is that all? No, we have left out the most important part, called the germ. The chick is formed neither from the yolk nor the "white," but from a minute "germ." This is a speck of life, but, by living on the large yellow yolk, and the transparent "white," it grows and grows, and by slow degrees becomes a perfect chick. The yolk is so large, and is such rich food, that it lasts until the chick is perfectly formed and ready to burst through the hard walls of its prison.

The baby fish is not so well off. It comes out of a tiny egg, in which is no room for a rich store of food for the germ  to live on. So, of course, it cannot wait within the egg until it is a perfect fish, but must come out and face the world as an imperfect one. In this baby form it is known as a larval  fish.

The bird baby is well off, for, on leaving the egg, it is a small copy of its parents, while the fish or frog, coming from a starved little egg, is merely a larva. It has to become a perfect fish or frog outside  the shelter of the egg! We might compare it with the child of poor parents, forced to go into the big world before it has really grown up!

Frogs' eggs are easy to keep: most of us have watched them hatch into tadpoles, and the tadpoles develop into small frogs. But fish-eggs are more difficult to keep: so let us suppose we have dived into the clear water of a sparkling stream where we can see the eggs of a trout. They were laid in the clean gravel bed, several hundred of them, nearly three months ago! Although the fish did her best to cover them over with gravel, many have been gobbled up by ducks, eels, and other enemies; but those that escaped are now ready to hatch.

Each egg breaks, and out wriggles a queer little object with two black discs on its head—its eyes. Can this odd-looking scrap of life ever become a handsome, strong, speckled trout? As it lies on its side, tired out with the exertion of escaping from prison, we notice a queer lump fastened to the underside of its body. What can it be?

It is a part of the egg-yolk; and for the next few weeks the baby fish depends on it for food. If you like, you can call it the baby's feeding-bottle. Only, as you will notice in our picture (below),  the feeding-bottle is not connected with the baby's mouth, but with its body! Why is that?

Trout Alevin—When first hatched, trout are known as "Alevin."

The reason is a strange one. The throat, or food-pipe, is at first closed up, therefore the baby would starve and die, but for the remains of egg-yolk  in the "feeding-bottle." This store of food keeps the little creature alive, and it can stay hidden away in the gravel while it is so weak and helpless.

So the weeks go by: our baby fish escapes its many enemies, comes out of hiding, and we see it chasing and eating small things, such as water-fleas.  Its food-bag  has now all gone. It begins to look more like a fish. It has a good appetite for small worms, grubs, and fresh-water  shrimps, and so grows up to be a lovely, shining, red-spotted  Trout.

Now all fish do not begin life quite in that way, but a great many do. As the eggs and babies have no nursery, and no parents to protect them, many are destroyed; to make up for this, each female fish must lay a great number of eggs. Some of our river-fish  lay many, but sea-fish  take first prize for huge families. The Cod, for instance, lays millions of eggs, the Flounder more than 1,000,000, and the Herring from 20,000 to 40,000!

The Herring, Cod, and most of the fish you see in the fish-shop, are very careless parents. They simply shed their spawn  into the sea, and swim away as if nothing had happened! We must notice, however, that they do not lay their eggs just anywhere  in the great ocean, but in certain parts. They choose suitable water, neither too cold nor too warm, neither too deep nor too shallow!

This habit is a most important one—for us as well as for them. The Herring likes to shed its eggs in fairly shallow water. The Cod gather in millions off the coast of Newfoundland, where the water is perfect for the eggs, the babies, and the grown-up Cod as well. Now fishermen study these habits of fish: they know when and where to find the mighty shoals of Herring as they travel to the spawning-beds: and we all know of the famous Cod-fishery of the foggy Banks of Newfoundland.

The eggs of these fish do not take months to hatch, like those of the Trout, but a few days only. When we consider the dangers they run it is surprising that so many fish remain! The shoals of Herring, for instance, are beyond count! In the year 1927 no fewer than 21 million of these fish were landed by Yarmouth fishing boats in one day,  and the total catch for one week, at this seaport only, was 85 million Herrings! 

All fish are not so careless of their eggs as the Herring, Cod, etc. The Trout and Salmon, for instance, hide them under gravel: others do more than this, and make nests: and some, like our common Stickleback, or "Red-Throat" as boys call him, even guard their eggs and young. Most of us have seen how fiercely this handsome little fellow guards his property. How he makes brave charges at intruders, with spines set like fixed bayonets. He is ready to fight anyone and everyone; in his Spring suit of green and red and gold, he shines like a jewel against the mud of his watery home.

Nest of Stickleback

Scattered all over the world are other nest-building fish: and, like the birds, each has its own idea of the best kind of nest to make. Strange to say, there are fish which have a special pocket of skin in which to carry the eggs. The common Pipe-fish (which you may see at the Zoo, or sometimes at the fish-shop, or in nets at the seaside) is one of these fish with pockets. Another queer fish, to be found in tropical seas (and also at the Zoo!) carries the eggs in its mouth and gills, until they hatch! Needless to say, this fish is content with a small family of 20 or 30.

Round our own coasts may be found fish which place their eggs in empty shells, and mount guard over them. Others there are which press their eggs into rock crevices, and protect them with their own bodies from roving enemies.

But fish that build nurseries, or guard their families in any way, are rare. As a rule, there is no nursery life for the baby fish. After leaving the egg, it finds itself helpless in a world of enemies. The chances are that it will soon be found by one of them, and speedily eaten!