62 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
E.—THEIR DANGERS AND FATALITIES. 
A general account of the fisheries of the North Atlantic coast of the 
United States is not to be completed without some mention of the 
agencies by which they are affected and reduced in abundance other 
than as the result of age. The variety of such influences is very great; 
perhaps more than in the case of the terrestrial vertebrates, and com- 
parable only to the affections and influences upon insects, which, like 
the fishes, oceur in overwhelming abundance at one time to ai more 
than decimated at another. 
We may consider the subject of the dangers and fatalities under 
three heads: first, those brought about by their fellow-inhabitants of 
the sea; second, by man ; and, third, by natural or physical causes and 
changes. 
1. FROM OTHER FORMS OF MARINE LIFE. 
The injuries caused by their fellow-inhabitants are twofold in their ac- 
tion: first, upon the eggs and embryonic fish, and second, upon the more 
fully grown fish. The destruction of the eggs of fishes is something 
truly enormous, the percentage of the yieid of even the youngest fish 
from a given number of eggs being extremely small. It has been c¢al- 
culated, in the-case of the salmon or shad, that not five eggs out of one 
thousand produce young fish, able to commence feeding, all the rest 
being destroyed in one way or another. It is quite likely that even this 
ratio is too large. A part of this loss of eggs is due, however, to im- 
perfect fertilization, and it is here that artificial propagation has the 
advantage in securing the contact of the milt with all the ripe eggs, 
leaving an insignificant fraction not fertilized. Probably not half, and 
sometimes even much less than half, the eggs discharged experience the 
same fortune in natural spawning. It would seem as if the immense 
disproportion of eggs to the resulting fish was an intentional provision 
in nature, to furnish food to the small inhabitants of the sea, especially 
to the young fish themselves, of various species, no other bait being so at- 
tractive to fish, even to those that have just laid the very eggs used for 
this purpose. The size of the eggs varies very greatly with the species, — 
as will be seen in a subsequent chapter, some being adapted to the 
smallest mouth, others requiring one of considerable capacity to take 
themin. There is almost no season of the year when fish eggs cannot be 
found in the water, either floating free or else adherent to some object, 
and the work of devouring them is carried on continually. Of course 
it is only the smaller fishes that pick up the small eggs ; but the former, 
in turn, contribute to some of larger size, and those to larger again, 
until finally, in the sequence, the largest inhabitants of the sea obtain 
their proper food. 
It is amon g the aquatic mammals that we find the most powerful de- 
stroyers of fish, these requiring a much larger amount in proportion 
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