XXII REPORT TO THE SECRETARY OF COMMERCE 
OYSTER INVESTIGATIONS © 
The oyster investigations were extended considerably during the 
last fiscal year and were as follows: (1) Experiments for increasing 
the collection of spat; (2) study of the factors controlling setting; 
(3) study of the spawning of the oyster; (4) surveys of natural 
oyster beds and reefs; and (5) study of the drill, chief enemy of the 
oyster. 
Inasmuch as the principal cause of the decline of the oyster indus- 
try in northern waters has been the inability to obtain a yearly crop 
of seed oysters, the purpose of experiments carried on at Milford 
Harbor, Conn., and Wareham River and Wellfleet, Mass., has been 
to discover a practical method of producing this annual supply. A 
new method for the control and production of seed oysters has been 
developed, which consists essentially in the establishment of spawn- 
ing beds in bays, harbors, and river mouths, and the planting of 
crates filled with shells in the vicinity of oyster beds for the collec- 
tion of set. 
The crates were triangular in shape, of spruce lath, having a 
capacity of 2 bushels, and each covering an area of 2 square feet. 
They were planted in various formations on the tidal flats, so as to 
determine their efficacy as seed collectors and the effect of their posi- 
tion and arrangement on the uniformity or intensity of the set. In 
Milford Harbor 300 crates collected an average of 2,000 spat per 
bushel of oyster shells. Fifty crates were set in Wareham River, 
Mass., and yielded from 1,900 to 45,000 spat per bushel. Setting 
occurs here between tide marks and was found to be heaviest about 
114 feet above the bar on which shells are planted by the local oyster 
men. In Wellfleet 97 crates were planted, and, though no set of com- 
mercial importance occurred, the crates in Herring River collected a 
fairly good set, ranging from 1,200 to 2,800 per bushel. 
Additional experiments and observations on the factors controlling 
setting have been undertaken in Long Island Sound by means of 
drift bottles, tide gauge, current meter, and spat collectors. 
The following practical applications of the experiments can be 
made: (1) In certain localities the oysters can be induced to spawn 
by adding sperm to the water, and (2) for successful spawning the 
oysters should be planted on the spawning grounds as densely as 
possible. 
At the request of the States, surveys of the oyster grounds were 
made in Massachusetts, North Carolina, South Carolina, Alabama, 
Mississippi, and Texas, to ascertain the practical measures suitable 
for each region that should be adopted in order to prevent further 
depletion of the natural reefs and to maintain or, if possible, to 
increase the production of oysters. 
It has been found that in certain regions in Massachusetts, as, for 
example, Wareham River, Onset Harbor, and Centerville River, the 
production of seed oysters can be increased considerably by adoption 
of a new method of spat collection and by restocking the depleted 
oyster beds (Centerville River). The other localities (Waquoit, 
Cotuit, and Chatham) are suitable as oyster-growing grounds only. 
In South Carolina oyster production can be increased by trans- 
planting seed oysters from the tidal flats to the bottoms below low- 
water mark, where setting does not occur. It has been recommended 
