58 OYSTER BEDS OF JAMES RIVER, VIRGINIA. 
summaries of the estimated total contents of market oysters, as 
distributed by rocks and varying densities of growth. These esti- 
mates are interesting, but are misleading if regarded as a measure of 
productiveness, for a very sparse growth over a large area, as compared 
with a dense growth over a small one, will give a great aggregate 
which really represents nothing commercially, as the oysters may 
be so thinly scattered as to be totally unavailable industrially. 
The important point is not how many oysters there may be on 
a given bed at a given time, but the quantity of oysters available 
under existing local economic conditions, the maximum number 
of bushels that can be removed with profit to the tonger. 
It is unnecessary to explain to those familiar with the oyster 
industry that it is practically impossible to accomplish a complete 
denudation of the beds in any one season, but there are cases known 
to the writer, though he has no personal knowledge of the kind in 
the region under discussion, in which small rocks have been, in effect, 
taken up bodily, oysters, seed, and shells, and transferred to planted 
beds. 
Under ordinary circumstances, in localities where the cull laws 
can be and are reasonably enforced, not only the seed or young 
oysters but a considerable proportion of the market oysters are left 
on the beds at the end of the season. Eventually, however, the 
oysters become so scattered that the daily yield to the tonger be- 
comes less than a minimum daily wage, and while the aggregate 
quantity of marketable oysters left on the beds appears large when 
expressed in a total of bushels, as in the tables of total contents, it 
will no longer pay to take them. The minimum average density of 
growth to which a bed may be reduced before becoming commer- 
cially unproductive depends primarily upon the price of oysters. 
The smaller the market value of a bushel of oysters the greater is 
the quantity that must be taken per day to furnish a living wage- 
Another factor that is essentially involved is the amount of culling 
required, less labor being necessary in handling the oysters when 
they are single or in small clusters than when they are badly clustered 
and overgrown with young, from which they must be separated 
before being placed on the market. 
The depth of water is also a very important factor in determining 
the actual density of growth necessary to render a bed commercially 
productive. As has been explained in describing the methods pur- 
sued in the preparation of this report, the deeper the water the 
greater must be the quantity of oysters per square yard or acre 
necessary to afford the tonger a given catch per day. Not only do 
his tongs of any given length of shaft and head cover a smaller area 
on the bottom, but the time and labor of making the “grab” — that is, 
putting the tongs on the bottom, scraping up the oysters, and pulling 
them up — are materially increased. In other words, in deep water 
