60 OYSTER BOTTOMS IN VICINITY OF APALACHICOLA, FLA. 
BARREN BOTTOMS. 
The area of barren bottoms—that is, those which are not naturally 
productive of oysters even in small quantities—vastly exceeds that of 
the natural beds, including in the latter those so-called depleted areas 
which bear practically nothing. These bottoms are barren, mainly 
because of one character in which they differ from the productive 
areas—namely, that they are devoid of shells or other objects lying 
on the surface. They consist of sand and mud of varying degrees of 
stability and consistency. Oysters, immediately after they develop 
from the egg, for a brief period swim or float freely in the water, 
settling to a fixed condition only after they reach a stage of consider- 
able development. ¢ 
Tt is not necessary to give more detail to this subject other than to 
say that at the time at which they are undergoing fixation the oysters 
are very minute, and aslight film of mud or slime is sufficient to stifle 
them. During the spawning season these little organisms are present 
in the water in untold myriads and are precipitated to the bottom in 
a continuous gentle drizzle of tiny specks. If they fall on an oyster 
bed they find firm supports on the shells and oysters, attach them- 
selves and grow, but if they fall on the mud or bare sand they die. 
The natural beds have been slowly developed on bottom similar to 
that which surrounds them solely because through some agency there 
originally lodged on the mud or sand some hard objects to which 
the young oysters could safely cling. Oysters developing there and 
their shells scattered about by the waves furnished additional places 
for fixation of new generations of young, with the result that the 
original growth extended in area and its bed became a compact 
mass of shells and fragments, beneath which can still be found by 
excavation or probing the original bottom differing in no essential 
particular from the adjacent barren areas. 
All that is required by the barren bottom in order that it may 
become productive is that its surface should be supplied with hard 
objects or cultch, either through natural agencies or by the hand of 
man. The capacity of the bottom to sustain material deposited on 
it and to maintain it in proper condition to serve as cultch depends © 
largely on its stability and consistency. Moving sands gradually 
cover objects deposited on their surface and soft mud permits them 
to sink. It is therefore of prime importance for the oyster culturist 
to have information concerning the character of the bottom, and it 
was one of the purposes of the survey to supply it. 
The methods and the instrument employed have been described in 
the introductory part of this report, and the results attained are shown 
graphically on the chart. 
@ For a more extended account see ‘‘Oysters and methods of oyster gulture,” by H. F. Moore, Bureau of 
Fisheries document no. 349, which may be obtained by application to the Bureau at Washington, D. C. 
