76 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
giants among the true fishes, such as the swordfish, the tunny or horse- 
mackerel, &c., which in turn have their antagonists as already men- 
tioned. é 
The seals, too, devour the larger fish in great quantities ; and in turn 
they are attacked by the cetaceans, such as the orea, or killer whales, and 
other kinds especially adapted for their destruction. Again, the whales 
are also antagonized by the killers and various species of swordfish ; 
and, indeed, possibly with the exception of the sperm whale, there is no 
animal in the sea but what has its foe. Man, however, presents him- 
self as the enemy and antagonist of all the species, and is provided with 
means for their capture. 
We have already referred to the abundance of vegetable matter in the 
sea, and to the possibility of supplying it in sufficient quantity to serve 
as the basis of marine animal life, and the marine zoologist will have no 
difficulty in understanding how the countless numbers of fish in the 
ocean obtain their food, in view of the myriads of crustacea, of mollusks, 
of worms, &¢., which inhabit the waters. 
It is not the species that remain in or near the bottom that are of the 
most importance, but the free swimming and floating forms that are 
most extensively and readily devoured. While at no time does the 
apparatus of the zoologist fail to reveal the presence of animal life, 
even though of microscopic dimensions, at times this manifests itself in 
bodies, the masses of which almost stagger the imagination, the sea for 
hundreds of miles in extent being an animated mush, what with shrimps 
and other crustaceans, salpz, and larve of mollusks, worms, &e., a 
bucketful of water taken indiscriminately over the entire areaseems 
filled with animal life. Nor are these organisms confined to the surface, 
the evidence of the beam-trawl and the dredge revealing its existence 
in equal quantities below. Various species of minute crustacea are not 
unfrequently thrown in masses on the beach, so as to constitute wind- 
rows of many miles in extent, this of course being but a small percent- 
age of what is left behind. Where these smaller animals are aggre- 
gated in unusual numbers are generally to be found great schools of 
mackerel, herring; whales, and other animals pursuing them, as though” 
certain definite instincts of migration influence them, or they are driven 
in their season in a definite direction. Schools of fish follow, which are 
thus brought more nearly to the nets of the fishermen. Indeed, generally 
the movements of the fish are directed by the instinct of reproduction, 
in which they aim at finding a suitable locality for the deposit of their 
spawn, or in search of food, which they either follow or travel to meet. — 
Among the inhabitants of the deep sea which serve as food for the 
larger fishes and cetaceans are probably various forms of the cephalo- 
pods or cuttle-fish, of which the stomach of the sperm whale frequently 
contains large masses, proving their occurrence of dimensions far be- 
yond those of which actual critical observation has yet been made. I 
will, therefore, be readily understood, from what has already bee 
7” . 



