REPORT OF THE COMMISSIONER OF FISHERIES. 83 
found, too, that there was some danger in the application of lime, a 
variation in the methods previously used having resulted in the 
destruction of a large proportion of the diatoms. At the close of the 
fiscal year, experiments were being conducted with extremely attenu- 
ated solutions of copper sulphate, after the method of water purifica- 
tion developed and recommended by the Department of Agriculture. 
A second difficulty was the gradual freshening of the water in the 
claire during periods of excessive rainfall. To overcome this, a pro- 
peller pump was installed to maintain constant fullness of the pond by 
pumping water from the bay to replace that lost by evaporation, the 
pump being driven by the same engine which operated the propeller 
for maintaining currents. The results were entirely satisfactory. 
In general it may be stated that the feasibility of fattening oysters 
by this method has been amply demonstrated, but owing to the many 
unforseen difficulties and delays encountered, it has not been possible 
to operate the claire at its full capacity, and the commercial possibili- 
ties of the system have not yet been developed. 
Experiments on the North Carolina coast.—The experiments and 
investigations in oyster planting and oyster culture begun on the North 
Carolina coast in 1902, in collaboration with the geological and nat- 
ural history survey of North Carolina, have been continued by the 
Bureau through the Beaufort laboratory. The work has been con- 
ducted in Pamlico Sound and Newport and North rivers, but in the 
past fiscal year was confined to Pamlico Sound. 
The object of these experiments is primarily to ascertain to what 
extent and with what profit the great areas in this region now barren 
of oysters may be made productive, whether the absence of oysters in 
a special region is due to other causes than the lack of cultch, and what 
method of planting is best suited to the particular combination of con- 
ditions (bottom, depth, abundance of spat, salinity, food, etc.) prevail- 
ing in a particular locality. 
Private planting seems to be on the increase; while yet very limited, 
it is apparently more common and more profitable than it was a few 
years ago. In at least one region (Portsmouth) such planting has 
already proved to be cramped by the scarcity of ‘‘seed.” Large areas 
convenient to such places, but not adapted to yield a market product, 
might be utilized by private persons or by the state for growing seed 
oysters. It is also to be determined whether the present natural beds 
may be artificially enlarged. 
Thirty plants were made during 1904, there being now a total of 35 
plants in 13 localities. Some of these plants have been made not with 
the immediate object of creating small oyster rocks, but to answer cer- 
tain definite questions; for instance, before making extensive plants 
in doubtful places it is advisable to ascertain whether spat will catch 
in such an area, and to what extent sanding up or sinking in the mud 
