PROGRESS IN BIOLOGICAL INQUIRIES, 1938 57 
by Dr. H. F. Prytherch during the past year at Beaufort, N. C., in 
the study of this problem, were to determine (1) the rate and char- 
acter of growth of seed oysters fastened to panels of cement, wood, 
and wire placed at different tidal levels, (2) the practicability of using 
devices of this type for intensive oyster culture, and (3) the possibility 
of utilizing specially constructed salt marsh ponds for concentrated 
growing of oysters by controlling setting, and preventing injury to 
the shells by the boring sponge. , 
One hundred and eighty seed oysters were attached to cement panels 
and studied individually with respect to growth in weight, volume, 
length, and width in relation to their position above and below low- 
water level and their orientation on the panels. The seed used were 
1 year old, uniform in size and shape, and showed the following aver- 
age measurements per oyster: Weight, 15.5 g.; volume, 95 cc.; length, 
51 mim. (2% in.) ; and width, 30 mm. (114 in.). Three series of panels 
were placed at the main pier in Beaufort Harbor so that series No. 1 
was 1 foot above mean low-water mark, series No. 2, 1 foot below this 
level, and series No. 3 on the bottom, or 6 feet below low-water mark. 
Each series consisted of 60 seed oysters that were cemented in groups 
of 10 on 6 panels and oriented in the following 6 different positions: 
Horizontal with left valve down, horizontal with left valve up, ver- 
tical with hinge up, vertical with hinge down, sideways with mouth 
up, and sideways with mouth down. Special care was taken to ar- 
range the panels so that all the oysters in each series had the same 
environmental conditions. 
The principal results of these experiments, briefly summarized, 
demonstrate that (1) the growth of oysters is most rapid in the tidal 
zone immediately above low-water level and slowest on the bottom, 
(2) the greatest increase in weight and size occurs in seed placed in a 
vertical position with the hinge uppermost, regardless of tidal level, 
(3) the next best growing position is sideways with the mouth of the 
oyster upwards, which produces the finest shape and depth of shell, 
and (4) the procedure of attaching seed to panels, screens, etc., and 
placing them in the most favorable tidal zone and individual positions, 
as indicated above, will yield an increase in volume of over 400 percent 
during the first year. 
The remarkable growth obtained with the best group of oysters of 
the entire series showed the following increase during the first year: 
Weight, 360 percent; volume, 410 percent; length, 100 percent; and 
width, 94 percent. Every oyster of this group attained a good size 
and shape and exhibited unusual individual growth that ranged from 
an inerease of 190 to 575 percent in weight, and from 210 percent 
to over 660 percent in volume. The results obtained thus far by the 
panel method of intensive oyster culture are encouraging as they 
indicate that a yield of over 5 bushels of marketable oysters, with a 
value of $5.00, may be obtained from 1 bushel of seed having an 
initial cost of 25 cents. This permits an expense of several dollars 
to cover the operations of placing each bushel of seed on panels and 
caring for them over a 2-year period. Studies are being continued 
to perfect an inexpensive type of panel that can be used indefinitely, 
and to improve the temporary coating that was applied to the shells 
of the oysters to protect them from attachment of spat, barnacles, 
boring sponge, etc. 
