FISHES OF OUR NORTH ATLANTIC SEABOARD 
25 
Where stream pollution is the chief 
cause of the decline of the fisheries, 
nothing except radical protective legisla¬ 
tion to save the streams will avail. The 
Government has found that a pound of 
bark to 30 gallons of water will kill Bass 
in one day, and that even a pound of chips 
to seven gallons of water is fatal to Sal¬ 
mon fry. 
If such simple pollutions as these de¬ 
stroy fish by the wholesale, what destruc¬ 
tion is wrought by oil and tar, sludge and 
bilge! 
Overfishing may be combated in two 
ways—by artificial propagation and by 
restricting the catch, either as to season 
or as to size—in short, applying common 
sense. 
Artificial propagation has proved its 
value in the case of fresh-water and an- 
adromous fishes. The Shad fishery con¬ 
tinues only because the U. S. Bureau of 
Fisheries has preserved it by artificial prop¬ 
agation. The same is true of the Salmon. 
THE “dangerous AGe’’ IN FISHES 
But for marine fishes, authorities differ 
as to the value of methods at present em¬ 
ployed. As new knowledge of the sea is 
gathered, however, there come reasons to 
believe that conditions may be established 
under which artificial propagation can be 
made a success. 
It has been found lately that there is a 
dangerous age for the fry of fish, just as 
there is for the children of men. We 
know that more children die between the 
day of their birth and their second birth¬ 
day than during the next twenty years, 
because of the high mortality from dis¬ 
eases of infancy. 
Likewise, it has been demonstrated that 
the first few weeks of a fishling’s career 
constitute a high mortality period, in 
which thousands die where one survives. 
PLANKTON AND ITS RELATION TO 
FISH LIFE 
If safe artificial methods could be de¬ 
vised to bring the fry past the critical 
period, their chances of survival would 
be vastly improved. It has been found 
that usually this period of wholesale deci¬ 
mation is reached about the time of the 
absorption of the yolk sac. 
Apparently at or before this stage mi¬ 
nute forms of plankton—the mass of 
passively floating or weakly swimming 
plant and animal life near the surface of 
the sea—are needed as food by the fry 
that can no longer draw on the yolk sac 
for nourishment, and without this plank¬ 
ton they die. 
The scarcity or abundance of plankton 
has been found to depend upon sunlight 
and temperature, and the examination of 
the scales of fish reveals that in any 
school of adults there is a great prepon¬ 
derance of some particular age. Figuring 
back, this class coincides with the year 
most favorable to the development of 
plankton. 
This affords a clue to the discovery of 
a method by which marine hatcheries may 
bring their salt-water fry past the dan¬ 
gerous age before releasing them—a thing 
that cannot now be done. 
This line of investigation shows how 
important the study of marine life is, 
what invaluable revelations it may yield, 
and the splendid character of the results 
that may be attained therefrom. 
The United States Bureau of Fisheries 
has recently published a paper on the 
Lobster which shows how an understand¬ 
ing of marine life leads to a solution of 
the problem of its conservation. 
SAVING THE LOBSTER FISHERY 
To meet the alarming decline of the 
Lobster fishery, the several States inter¬ 
ested in its protection have enacted vari¬ 
ous laws. Some have provisions for a 
closed season, in which the taking of this 
crustacean is forbidden. Laws prohibit¬ 
ing the destruction of female Lobsters 
“in berry”—that is, carrying their eggs 
after laying them—have also been en¬ 
acted. 
In addition to the protection thus 
offered, attempts have been made to prop¬ 
agate them artificially, by hatching and 
liberating the fry. 
Existing policies, however, have not 
checked the decline, and recent studies 
show that new forms of protection and 
propagation must be adopted if the fishery 
is to be saved. Dr. Herrick, America’s 
foremost student of the Lobster problem, 
proposes the abolition of the closed season, 
which he considers a futile practice. He 
would adopt a double gauge, under which 
traps would be prohibited that did not 
permit the escape of all Lobsters under 9 
inches, and make impossible the entrance 
