THE SEA FISHERIES OF EASTERN NORTH AMERICA. 67 
part of his food from the sea, and drawing upon it for supplying dis- 
tant localities, or laying up stores for seasons when fish could not be 
readily obtained. These fisheries in the northern hemisphere are par- 
ticularly extensive, a large portion of the population of both shores of 
the Atlantic finding extended employment in this vocation. The her- 
ring fisheries of Scandinavia, Holland, and Great Britain, and in less 
degree of British America and New England, the fisheries for cod and 
other Gadide in the entire North Atiantic, the capture of halibut, salmon, 
&e., are all included in this list. In the North Pacific Ocean the sal- 
mon and cod represent for the most part this industry. In the warmer 
countries of the world, although fish are perhaps absolutely as abun- 
dant as in the north, they can be used only for daily consumption, it 
being found almost impossible to salt or dry them for future use; and 
hence the anomaly of vast importation of cod, herring, and other salted 
-and dried fish into Cuba, the West Indies, and South America, when 
these regions can show much better food-fish in countless abundance. 
Great, however, as is the destruction of fishes by man in his various 
fisheries, it can easily be shown that it constitutes a very insignificant 
portion of the slaughter, when compared with what is effected by fishes 
themselves, and it may safely be said that the total of the fisheries of 
the North Atlantic and Pacific for the year does not equal the destruc- 
tion, possibly in a single hour, by other causes. 
We are apt to ascribe a very undue influence to human agencies in af.- 
fecting the supply of fish by positive diminution or by direct extermina- 
tion. That man does influence the supply to some extent may readily 
be conceded, especially in the case of the anadromous fish. The obstruc- 
tions of rivers by dams are among the most important. The other 
agencies of poisoning the water by refuse from factories, have little 
weight excepting in rivers, scarcely attaching to bays and shores. It is 
even a question whether, in some instances, man does really increase_ 
the food supply by the destruction of certain forms that are predaceous. 
Reference has already been made to the great problem whether the pur- 
suit of the bluefish by the Gloucester fishermen on the eastern coast of 
_ the United States is attended by a further increase of the fish on which 
it especially preys, such as the menhaden, scup, weakfish, &c., and 
whether every shark and every porpoise killed by man also gives a new 
lease of life to a great number of fishes. 
F1 A movement now (1877) on foot promises to add another to the illus- 
_ trations of man’s indirect influence upon the fisheries in the disturbance 
of the balance of power. It has been ascertained that by treating fish 
with bisulphide of carbon or benzine the oil can be extracted much. 
more easily than by the ordinary process, leaving, indeed, a residuum 
in the form of a dry powder. It is claimed that the by-product of oilis 
about £0 per cent. more than by the kettle or presses, and the dried 
serap instead of yielding 10.5 per cent. of ammonia produces 14. 
A building is now being erected at Wood’s Holl (85 feet by 40, and 



