periods at high speed while those with rounded or squarish tails, although
capable of sudden bursts of speed, are usually slow swimmers.

There is an interesting reason, too, why the under side of the herring
is silvery white while its back is steely blue and black. It is a case of
protective colouring. Looked at from above by hungry birds for instance
the metallic colours of its back merge into the tones of the sea. Looked at
from below by larger fish seeking their prey, the silvery white of the belly
renders it inconspicuous when seen against a light sky. So you see its
beautiful colouring is really a protection against its enemies from the air
above and from the water beneath.

Unlike nearly every other food fish, herring eggs are laid on the bottom
of the sea. They are sticky and become attached to seaweed and stones.
Only a small fraction of the eggs laid come to maturity because when the
herring shoals gather together for spawning they are followed by myriads of
hungry fish ready to devour the female "hard roe" deposited on the bed of
the sea.

There is no fear however of the herring dying out because of this
devastation. Although they lay rather fewer eggs than most fish of their
size the average family for each mother is at least 30,000 a year! It has
been calculated that if all the,se eggs came to maturity the seas would be
solid with herrings in a very few years, so you see it is just as well that there
is some amount of thinning out.

When the little fish hatch out they drift helplessly with the tides for a
while but gradually come to the surface to feed. At this stage the helpless
little creatures, borne hither and thither by the currents, don't look in the
least like herrings.

When they are about an inch and a half long they come into the estuaries
and along the shores in millions and begin to develop their silvery sheen.
The scales appear and at this stage they are caught as whitebait. Whitebait,
however, is not young herring only, but a mixture of them with other small
fishes, chiefly sprats.

When the herrings are six to eight inches long they leave their nurseries
and move to the rich feeding grounds off shore. At three years old some
develop roes and prepare to breed, while others—though fat little fish—
do not become mature for another year. These are often caught when they
congregate on the feeding grounds and that is one reason why, when you
buy herrings, particularly in June and July and ask the fishmonger what he
has done with the roes he assures you that "they haven't any."

These are not the only herrings without roes. There are the mature
fish who have spawned, but they are too watery and thin to be worth eating
until they have fattened up again when there is no reason why they should
not be caught. But there are so many points around the British Isles where
herrings congregate to spawn at different times of the year that there are
very few months when herrings with roes are not available in some
market or other.

What do the herrings live on ? They feed principally on the plankton
or swarms of microscopic organisms, both animal and vegetable, that float on
or near the surface of the sea.   As might be expected from the nature of their