OYSTER PROPAGATION IN Le Dele 55 
SESSIONAL PAPER No. 38a 
interferes with feeding, causing ultimate starvation. Silt that settles may be abun- 
dant enough to bury oysters; but even an exceedingly thin layer deposited on the 
objects used as cultch by the spat, will prevent fixation and therefore to the same 
degree prevent propagation. Assuming the spat to have secured fixation, it takes 
proportionately less silt to smother these delicate tiny oysters, than will bury the 
adults. 
The main cause of the destruction of natural oyster beds in historic times has been 
improper and careless fishing. The history of the oyster industry everywhere has 
shown that when oyster fishing has been pursued under no other regulations than 
those born of the wishes of the fishermen themselves, the natural beds were rapidly 
depleted, and finally exterminated, unless remedial measures were undertaken. Accord- 
ingly there have arisen many laws regulating this fishery, that seem strange to those 
engaged in private farming. For example, oysters may not be taken from natural 
beds except during the “open season.” The “close season,” during summer, varies 
greatly in its limits according to locality, but usually includes May, June, July, and 
August. Fishing must be confined to the hours between sunrise and sunset. Oysters 
may be taken with tongs but not with rakes; and dredges may not be used, nor may 
oysters be taken through the ice. Oysters may not be sold under three inches in 
length, and those smaller than this must be returned to the beds, etc. These laws are 
enforced by police methods; and fines and penalties are imposed for a breach of their 
provisions. 
Under private culture each farmer tries to promote his own ultimate best 
interests, and thus also the public welfare; but those who share in a public fishery 
consider only their own immediate self-interest. They sacrifice their own future, as 
well as the public welfare. The oyster laws are a result of an honest and fairly intelli- 
gent endeavour to conserve the natural oyster resources, and they undoubtedly partly 
succeed in effecting their object. It will be instructive to consider for a while the 
question of the depletion of natural beds and their conservation. 
AGENCIES DESTRUCTIVE TO OYSTERS. 
It is a fundamental biological principle that the agencies that destroy the indi- 
viduals of any living species nearly balance the natural rate of increase; that after 
a species has established itself in any locality the number of its population remains. 
nearly the same from year to year, though the balance between birth-rate and death- 
rate will fluctuate slightly up and down as one or the other set of factors increases 
or decreases. For instance, if food becomes temporarily more abundant, there is an 
increase in population, while a decrease in food results in a reduction of individuals, 
through starvation. So likewise there will be fluctuation due to the prevalence of 
various enemies and epidemics. 
Under this law there must be as many deaths as births; or, vice versa, the number 
of births must be sufficient to make good the loss by death. Therefore, we can judge 
of the extent of the destructive forces by simply noting the fecundity of a species. 
The oyster is one of the most prolific of all creatures. A single large ‘‘ spawner” 
has been estimated to produce annually sixty million eggs, but we must remember 
that half of the oysters are males, and that there are many small oysters. Neglect- 
ing the very small “seed” oysters, we may conservatively say that an oyster bed 
produces from ten to fifteen million young for each adult present; so that, if all lived 
and there were no further propagation, an oyster bed would be ten million times larger 
in five years. In spite of this astounding conclusion, however, the oyster beds are 
being depleted simply from the annual removal of a few hundreds or thousands of 
barrels. This should be the most convincing proof that the natural foes of oysters 
are extraordinarily formidable. Then why may we not believe that the destruction 
caused by man is insignificant in comparison, and so need not be considered to have 
