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BULLETIN OF THE BUREAU OF FISHERIES 
In addition to variations in the number of spat per branch it was also found that 
the distribution of spat showed marked differences according to the direction and 
velocity of the tidal currents, the height of the collector from the bottom, and the 
range of tide on the days when setting occurred. The setting of the oyster larvae 
in Milford Harbor occurred chiefly at the surface at low slackwater and continued 
until the flood tide had risen approximately 1 % feet above mean low-water mark. 
This was clearly shown also by the distribution of the spat on the brush on which 
they were found to be located on all sides of the main branches in a zone from the 
bottom to 3 inches above, while above this level they were chiefly on the lee side of 
each branch and became less numerous as the current and height of water increased. 
The smaller twigs on the branches offered very little resistance to the currents and 
consequently no spat were found attached to them, except in a few cases where the 
twigs were very close to the bottom and in the low slack-water zone. 
The experiments in Milford Harbor have shown, however, that brush collectors 
can rarely be used successfully in northern waters because of the comparatively light 
setting, slow growth of spat and necessity of transplanting and anchoring the branches 
in deep water before the first winter. However, satisfactory results have been 
obtained in southern waters or in regions where setting is heavy and growth of the 
spat rapid. This has been demonstrated by experiments made in South Carolina and 
Georgia in which branches 4 to 8 feet long, having a diameter of the butt of about 
1-inch were found to be most suitable. (Galtsoff and Luce, 1930.) Where the 
tidal currents are strong it is best to plant the branches in conical stacks, so that the 
smaller twigs are closely bunched, to facilitate the attachment of the oyster larvse 
by creating eddies. Oak brush was successfully used in Georgia and South Carolina 
and birch in Connecticut, though for this purpose almost any kind can be used. 
The advantages of using brush are: 
1. It offers considerable surface area for the attachment of the oyster spat. 
2. Oysters growing on the convex surface of the branches are less crowded and 
have a better shape than those attached to shells. 
3. The brush keeps the seed oysters above the bottom, thereby increasing their 
growth and protecting them to a certain extent from natural enemies. 
4. It disintegrates in about a year or is destroyed by shipworms, so that the 
seed oysters attached to it break apart or can be separated as single specimens. 
5. It can be used on mud flats that are useless for the planting of shells. 
6. It is a cheap material for the collection of seed oysters and is easily obtained. 
A series of experiments was undertaken to demonstrate the suitability of tiles 
as seed collectors. The tiles used were half-round glazed sewer pipe having a diameter 
of 12 inches and length of 2 feet. The surface of the tiles was approximately 1,000 
square inches and the average number of spat collected per tile was 1,500 from the 
first set and 4,000 from the second or heaviest set. The setting on the tiles, of course, 
was not uniform but decreased in intensity from the bottom to the upper setting 
limit. The setting on tiles planted at low-water mark in vertical positions is shown in 
Figure 31. The spat, which were attached to them, were allowed to grow until late 
fall and were then detached from the tiles without the slighest injury and transplanted 
as single seed oysters. 
The third type of seed collector used in 1925 was that suggested by Capt. Charles 
E. Wheeler, of the Connecticut Oyster Farms Co. It consisted of a round galvanized 
wire bushel basket which was filled with shells and then set out on the tidal flats. 
A dozen of these baskets were filled with either oyster, clam, or mussel shells, and 
