260 
BULLETIN OF THE BUREAU OF FISHERIES 
with wire-bag collectors in various localities of Connecticut shores and in Great 
South Bay, N. Y., is given in Table 32. 
Table 32.— i Summary of results obtained with the wire-bag type of seed-oyster collector 
Observations 
1927 
1928 
Milford 
Harbor 
Great 
South 
Bay 
Milford 
Harbor 
Other 
Connecticut 
harbors 
2,450 
3, 500 
1, 500 
9 
50 
95 
18, 000 
22, 000 
7,500 
75 
150 
90 
15. 000 
26. 000 
9, 000 
60 
85 
99 
15, 000-20, 000 
25, 000 
5,000 
70 
100 
90-98 
Maximum number of spat per shell. . _ __ 
Per cent of shells covered with spat __ 
V. CONCLUSIONS 
By P. S. GALTSOFF and H. F. PRYTHERCH 
Observations and experiments carried out by the authors from 1925 to 1928 
along the coast of Cape Cod and in Long Island Sound indicate that there exist many 
thousands of acres of formerly productive bottoms which at present are depleted to 
such an extent that it is difficult to find a few live oysters on them. These areas 
can be rehabilitated by the establishment of spawning grounds and by employment 
of spat collectors for obtaining seed oysters. Since suitable bottoms for collecting 
the set are limited, it is necessary to employ such devices as crates, shell bags, or brush 
in order to present a greater area of surface for the attachment of the oyster larvse. 
It has been demonstrated that by means of the bags (3 feet long, 1 foot in diam- 
eter) made of poultry wire, filled with oyster shells, and stacked in various formations 
the number of seed oysters collected per a given area of bottom can be materially 
increased. In Wareham River from 15 to 30 times as many seed oysters were col- 
lected on a given area as by ordinary methods. In Onset Bay the number of spat, 
per a unit of area, in one layer of horizontally laid bags was 4 times greater than on 
the adjacent bar. Since it is possible to put 3 or 4 layers of bags over 1 square yard 
the productivity of seed oysters in that bay can be increased from 12 to 16 times as 
compared with the present method of planting. In the experiments at Milford 
Harbor 45 times as many seed oysters per given area were obtained in the stocks of 
bags as on loose shells scattered over the bottom. 
A success with the wire-bag collectors depends on several conditions. There 
must be sufficient number of spawners (at least 500 bushels to an acre) in the vicinity 
of the collectors. The temperature of the water must be above 20° C. because no 
spawning takes place below that temperature. The surface of shells or other cultch 
must be clean since slime or overgrowth of algae prevent the attachment of the larvae. 
The bags must be planted in the zone of heaviest setting which could be determined 
either by preliminary experiments or by a careful examination of piles, wharves, 
and other underwater structures or objects. 
Crates and wire-bag collectors can be successfully used either on soft bottoms or 
on sandy and shifting bars where ordinary planting of shells is impossible. 
Though the production of seed oysters varies somewhat from year to year, the 
relative intensity of setting that will occur each season can be estimated a month 
or more in advance from the examination of the gonad development of the oysters 
