122 MARVELS OF FISH LIFE 
fish are not sardines at all. But the small-sized sardine 
is a one-year-old pilchard, whereas the larger size is 
merely an older pilchard. 
Of all our food fishes probably the mackerel is the 
most beautiful, with its alternating zig-zag bands of 
black and green, its metallic iridescence, ranging from 
a silvery hue to a coppery gold, and its changing colours 
from a yellow to a beautiful pink. 
In the spring and early summer mackerel feed on 
minute free-swimming crustaceans, such as copepods, and 
mysis (a mysis is illustrated on the plate facing p. 152), 
and on the medusa-fleas which frequent jelly fish. This 
food is strained from the water by the gill-rakers of the 
fish which are as well developed in the mackerel as in 
the herring. In the late summer and autumn mackerel 
feed on small pilchards, sprats, rocklings and sand 
eels. 
The mackerel is a summer spawner, and the floating 
eggs are found round our shores in May and June. 
The seasonal migrations of this fish have always 
attracted great interest. Broadly speaking, the mackerel 
is practically absent from the Cornish coast from Novem- 
ber to January. With approaching spring it is caught 
in the Atlantic at first some distance out, but by May 
huge shoals have come right in shore. These fish are 
abundant during June and July, but become scarce in 
August and then disappear. They turn up again for a 
month late in September, and then again disappear 
until the following May. 
