PRODUCTION AND COLLECTION OF SEED OYSTERS 
235 
A series of experiments with wire-bag collectors was devised to determine the 
extent of the setting area and to find out the effect of elevation (with the reference 
to the low-water mark) upon the density of setting. In 1927, 950 bags were planted 
at 9 stations; they were placed either singly on the bottom, stacked in a group of 6 
or 8 (fig. 21, 22), or piled irregularly on the bars. In order to determine the level of 
maximum setting, 400 bags were arranged in 8 rows at Shell Point extending across 
the bar from 1 foot below low-water mark to 4 feet above. After September 1, 10 
bags were taken at random from every row, emptied, the shells were well mixed up, 
and 1 peck of them taken for counting the spat. The results of the counts are 
presented in Table 21. Although there was a considerable variation in the number 
of spat in the bags of the same row, it is evident from an examination of Table 21 
and Figure 23 that the maximum density of setting occurred in the zone of from 1. 5 to 
2 feet above low-water mark. No setting was found at high-water level (4 feet). 
It has been noticed also that the spat was well distributed throughout each bag, only 
about 10 per cent of shells being blank. From a commercial point of view, the 
setting in the bags planted in various sections of the bar was fair; in the zone between 
low-water mark and 2 feet above, it averaged 5$ 898 spats to a bushel. Setting on 
shells thrown on the bar averaged 6,990 spats to a bushel and was more uniform 
than it was in the individual bags. (Table 22.) This shows that both loose shells 
and those in the bags have approximately the same concentration of spat, but taking 
into consideration the area of the bottom covered by one bushel of scattered shells 
and by one bag, the productivity in the bags was much higher. On the surface of 
Shell Point bar in the zone between 0. 5 and 2 feet above low water, there was on the 
average 86 scallop shells over each square foot, or about 0. 6 bushel of shell to a square 
yard (there were about 1,300 scallop shells to one bushel) bearing about 4,200 spats. 
Three bags laid horizontally over the area of 1 square yard at the same level caught 
on the average 5,900 spats to a bushel of shells or 17,700 spats per square yard. 
Thus the productivity in the bags was four and two-tenths times that of the shells 
scattered over the same area. By stacking the bags in various formations it is possible 
to put 8 or 10 of them over one square yard of the surface of the bar, thus utilizing the 
whole height (4 feet) of the setting zone and increasing its productivity materially. 
Table 21. — Vertical distribution of setting ( number of spat per bushel ) in Onset Bay, near Shell Point, 
1927 
[Wire-bag collectors] 
Position of the bag in relation to low water 
Bag No. 
—1 foot 
Low 
water 
+0.5 foot 
+1 foot 
+1. 5 feet 
+2 feet 
+3 feet 
+4 feet 
1 
2, 000 
3,100 
2,200 
4,700 
12, 200 
6,700 
2, 500 
No set. 
2 
3, 100 
6, 900 
2, 800 
3, 400 
7, 800 
7, 000 
1,400 
Do. 
3 
2, 000 
2, 700 
6, 000 
3, 700 
3, 200 
9, 400 
1,200 
Do. 
4 
1,300 
3, 100 
6, 800 
4, 200 
7, 900 
12,900 
1, 100 
Do. 
5 
3,500 
5, 300 
7, 500 
5, 900 
8,200 
4,800 
1,100 
Do. 
8 
2, 300 
4,500 
6, 200 
3, 600 
8, 400 
4, 400 
3, 500 
Do. 
7 
2,200 
4,000 
6, 900 
3, 000 
6,200 
12, 600 
3, 000 
Do. 
8 
1,900 
4, 900 
6, 600 
5, 100 
4, 200 
6, 000 
2,200 
Do. 
9 
900 
5, 800 
6, 800 
4,500 
10, 700 
4, 000 
1,600 
Do. 
10. 
1,400 
4,800 
6, 100 
4, 000 
6, 200 
2, 000 
4,000 
Do. 
Average 
2, 050 
4, 510 
5,790 
4, 210 
8, 000 
6, 980 
2, 160 
