nation of its movements, since the duties
of reproduction appear to be performed elsewhere. Like the tuna, the
bluefish, the bonito, and the squiteague, they pursue and prey upon the
schools of menhaden and mackerel, which are so abundant in the summer
months. "When you see swordfish, you may know that mackerel are about,"
said an old fisherman to me. "When you see the fin-back whale following
food, there you may find swordfish," said another. The swordfish also
feeds upon squid, which are at times abundant on our banks.

To what extent this fish is amenable to the influences of temperature is
an unsolved problem. We are met at the outset by the fact that they are
frequently taken on trawl lines which are set at the depth of one
hundred fathoms or more, on the offshore banks. We know that the
temperature of the water in these localities and at that depth is sure
to be less than 40 deg. Fahr. How is this fact to be reconciled with the
known habits of the fish, that it prefers the warmest weather of summer
and swims at the surface in water of temperature ranging from 55 deg. to
70 deg., sinking when cool winds blow below? The case seemed clear enough
until the inconvenient discovery was made that swordfish are taken on
bottom trawl lines. In other respects their habits agree closely with
those of the mackerel tribe, all the members of which seem sensitive to
slight changes in temperature, and which, as a rule, prefer temperature
in the neighborhood of 50 deg. or more.

[Illustration: SHINING IN THE SUNLIGHT]

[Illustration: THROWING WHITE WATER LIKE THE EXPLOSION OF A TORPEDO]

The appearance of the fish at the surface depends largely upon the
temperature. They are seen only upon quiet summer days, in the morning
before ten or eleven o'clock, and in the afternoon about four o'clock.
Old fishermen say that they rise when the mackerel rise, and when the
mackerel go down they go down also.

Regarding the winter abode of the swordfish, conjecture is useless. I
have already discussed this question at length with reference to the
menhaden and mackerel. With the swordfish the conditions are very
different. The former are known to spawn in our waters, and the schools
of young ones follow the old ones in toward the shores. The latter do
not spawn in our waters. We cannot well believe that they hibernate, nor
is the hypothesis of a sojourn in the middle strata of mid-ocean exactly
tenable. Perhaps they migrate to some distant