PROGRESS IN BIOLOGICAL INQUIRIES, 1926 655 
with which to combat this pest and know very little about the organism 
itself. We have decided, therefore, to include the investigation of the drill 
in our program. Doctor Federighi is conducting this investigation in Norfolk, 
Va., and will tell us about his plans and experiences. 
COLLECTOR EXPERIMENTS 
By H. F. PrRyYTHERCH 
As a foundation of this discussion I would like to describe conditions in the 
industry. On these we base all practical experiments and our study of the 
biology and environment of the oyster. The oyster industry in Connecticut 
represents the greatest development in the production of aquicultural crops. 
Here, we have man increasing production over nature by putting into opera- 
tion his own methods and appliances. In some areas in Connecticut where 
oysters were formerly very prolific, to-day you can not find an oyster under 
any circumstances. From experimental plantings it was found that grounds 
out in deep water—30 or 40 feet deep—were suited to growing oysters. When 
they began transplanting oysters from inshore regions to these beds they oc- 
casionally got a crop of seed oysters, which led to the extensive practice of 
planting shells in deep water for seed collection. In a short time this prac- 
tice failed to supply the industry, as conditions there are unsuitable for ob- 
taining a yearly crop of seed oysters, because deep water in Connecticut is 
not the natural environment chosen by the oyster. It’s choice has been the 
bays, harbors, and inshore regions, where food is more abundant and general 
conditions are more favorable. Milford Harbor was formerly a very prolific 
oyster-growing region, but practically no oysters were growing there when I 
first began studying; in fact, in 1925 we established two spawning beds in 
the harbor and put out several types of collectors. One type planted on the 
mud flats was birch brush; another type was glazed tile; and the third con- 
sisted in putting shells in baskets to see if oyster larve would go in there and 
attach to the old shells. The results of the first summer’s work were unusually 
good. A good set formed on the brush and was obtained on the tiles also. 
The wire baskets, however, were the most practical and the best collectors of 
all. In 1925 the shells in these baskets were found to contain about 15,000 
spat, so it was decided in the following year to carry on more extensive basket 
operations. In examining the baskets set out in 1925 we found that the larve 
had not penetrated into the center of the basket; so the following year we 
developed a triangular crate, which was stronger, cheaper to build, and gave 
much less distance for the oyster larvze to penetrate. We found, at Milford 
Harbor, in putting out these crates, that oyster larvyze penetrated into the very 
center of the containers. The baskets put out in 1926 collected about 2,000 
oyster larve, and though this was a smaller number than was collected in 
1925, it was, at the same time, a good commercial crop. The difference in the 
quantity can be traced to conditions on the spawning grounds. 
In experiments made with the crates in Massachusetts we found that the 
oyster larve attached only to the shells in the outer portion of the crate. In 
this case, scallop shells were used, which are smaller than the shells used at 
Milford Harbor, with the result that the oyster larve did not have the same 
chance of penetration. Controlled natural propagation has enabled us to use 
or restore these valuable inshore areas and utilize them for obtaining a maxi- 
mum production of seed oysters. Conditions in this area are suitable, not only 
for seed collection, but also, for growing adult oysters. 
There has been considerable comment lately with reference to artificial propa- 
gation as it applies to the oyster. I would like to discuss this phase a little, as 
I experimented with it for three years and understand the problems it presents. 
The fact that artificial propagation can be carried out successfully under 
laboratory conditions does not warrant conclusions that this method will be 
commercially practicable for the industry. However, I do not think that it 
will be possible ever to develop a method of artificial propagation that will 
produce in 10 years the amount of seed oysters that we produced in one summer 
in Milford Harbor. For example, in addition to the set on the crates, brush, 
etc., we collected over 100 bushels of seed oysters from a gravel bar in the 
harbor, averaging from 20,000 to 30,000 seed oysters to the bushel. That was 
only in an experimental way. To do that with any type of apparatus would be 
