184 BULLETIN OF THE BUREAU OF FISHERIES. 
Provinces, States, and counties; (3) the code of statutes must depend on the 
nature of the different species of animals it is designed to protect, the matter 
becoming, at bottom, one of natural history. 
In nearly all cases the final key to the situation is found in artificial propa- 
gation—the development of the hatchery. This demands, however, men who 
are willing to study their business and to learn thoroughly the nature of the 
fishes concerned—the egg, the fry, and the adult. Artificial hatching is not 
a process. It is an art, and like all arts it must rest on science. How much 
of the money spent on hatcheries has been wholly wasted no one can tell, but 
the amount is considerable. And the value of any hatchery is determined, 
not by the nominal output of eggs and fry but by the brains put into the business. 
Each species of fish, like each plant in the garden, has its own nature and must 
be met on its own ground. It is set in its ways and will not conform to the 
habits of any other species. 
The species of fishes affected by this legislation are numerous, but they 
cau be grouped into about six types, as represented by the herring, the white- 
fish, the red salmon of the Pacific, the black bass, the wall-eye, and the sturgeon. 
The herring is a marine fish existing in incalculable numbers and swarming 
by the million in many places on both shores of the North Atlantic. The catch 
of herring in navigable waters is less than a drop in the bucket, and the fishery 
statutes must concern the protection and regulation of the fishing industry 
rather than the conservation of the herring itself. 
The whitefish is a type of a group of fishes, part of them the helpless prey 
of the predatory fishes, the rest feeding freely on other forms, but all spawning 
in cooling waters, mostly in November. The eggs are large, free, and easily 
manipulated, so that they can be readily cared for by processes of artificial 
propagation. By caring for these eggs, perhaps twenty times as many young 
can be returned to the lake as would develop naturally. The best protection 
to such fishes is that of a size limit, forbidding the buying or selling of all that 
have not reached the degree of maturity involved in the second appearance 
on the spawning grounds. ‘These fishes are fit for the table while the spawning 
process is going on. To forego catching them for a month or so before the 
spawning period, then to allow free fishing for adult fish on the part of those 
fishermen prepared to preserve the spawn is the best means of maintaining 
and increasing fisheries of thistype. By this process the adult fishes are regarded 
as a ripened crop, which is removed to make way for the crop of next year. In 
this regard we already see every prospect of success in the Great Lakes, as 
even under present conditions, with the present hatchery facilities, the number 
of fishes of this kind is steadily increasing. 
To another category belongs the salmon of the Pacific coast, which feed 
in the sea, spawn in the rivers, ascending the streams for the most part when 
